1
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Vinograd I, Souliou SM, Haghighirad AA, Lacmann T, Caplan Y, Frachet M, Merz M, Garbarino G, Liu Y, Nakata S, Ishida K, Noad HML, Minola M, Keimer B, Orgad D, Hicks CW, Le Tacon M. Using strain to uncover the interplay between two- and three-dimensional charge density waves in high-temperature superconducting YBa 2Cu 3O y. Nat Commun 2024; 15:3277. [PMID: 38627407 PMCID: PMC11021565 DOI: 10.1038/s41467-024-47540-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Uniaxial pressure provides an efficient approach to control charge density waves in YBa2Cu3Oy. It can enhance the correlation volume of ubiquitous short-range two-dimensional charge-density-wave correlations, and induces a long-range three-dimensional charge density wave, otherwise only accessible at large magnetic fields. Here, we use x-ray diffraction to study the strain dependence of these charge density waves and uncover direct evidence for a form of competition between them. We show that this interplay is qualitatively described by including strain effects in a nonlinear sigma model of competing superconducting and charge-density-wave orders. Our analysis suggests that strain stabilizes the 3D charge density wave in the regions between disorder-pinned domains of 2D charge density waves, and that the two orders compete at the boundaries of these domains. No signatures of discommensurations nor of pair density waves are observed. From a broader perspective, our results underscore the potential of strain tuning as a powerful tool for probing competing orders in quantum materials.
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Affiliation(s)
- I Vinograd
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077, Göttingen, Germany
| | - S M Souliou
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
| | - A-A Haghighirad
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
| | - T Lacmann
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
| | - Y Caplan
- Racah Institute of Physics, The Hebrew University, Jerusalem, 91904, Israel
| | - M Frachet
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
| | - M Merz
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
- Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany
| | - G Garbarino
- ESRF, The European Synchrotron, 71, avenue des Martyrs, CS 40220, F-38043, Grenoble Cedex 9, France
| | - Y Liu
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - S Nakata
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - K Ishida
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - H M L Noad
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - M Minola
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - B Keimer
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - D Orgad
- Racah Institute of Physics, The Hebrew University, Jerusalem, 91904, Israel
| | - C W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - M Le Tacon
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131, Karlsruhe, Germany.
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2
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Chajewski G, Kaczorowski D. Discovery of Magnetic Phase Transitions in Heavy-Fermion Superconductor CeRh_{2}As_{2}. PHYSICAL REVIEW LETTERS 2024; 132:076504. [PMID: 38427882 DOI: 10.1103/physrevlett.132.076504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 01/17/2024] [Indexed: 03/03/2024]
Abstract
We report on the specific heat studies performed on a new generation of CeRh_{2}As_{2} single crystals. Superior quality of the samples and dedicated experimental protocol allowed us to observe an antiferromagneticlike behavior in the normal state and to detect the first-order phase transition of magnetic origin within the superconducting state of the compound. Although in the available literature the physical behavior of CeRh_{2}As_{2} is most often described with the use of quadrupole density wave scenario, we propose an alternative explanation using analogies to antiferromagnetic heavy-fermion superconductors CeRhIn_{5} and Ce_{2}RhIn_{8}.
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Affiliation(s)
- Grzegorz Chajewski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
| | - Dariusz Kaczorowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
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3
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Wang J, Spitaler M, Su YS, Zoch KM, Krellner C, Puphal P, Brown SE, Pustogow A. Controlled Frustration Release on the Kagome Lattice by Uniaxial-Strain Tuning. PHYSICAL REVIEW LETTERS 2023; 131:256501. [PMID: 38181349 DOI: 10.1103/physrevlett.131.256501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/26/2023] [Accepted: 11/16/2023] [Indexed: 01/07/2024]
Abstract
It is predicted that strongly interacting spins on a frustrated lattice may lead to a quantum disordered ground state or even form a quantum spin liquid with exotic low-energy excitations. However, a controlled tuning of the frustration strength, separating its effects from those of disorder and other factors, is pending. Here, we perform comprehensive ^{1}H NMR measurements on Y_{3}Cu_{9}(OH)_{19}Cl_{8} single crystals revealing an unusual Q[over →]=(1/3×1/3) antiferromagnetic state below T_{N}=2.2 K. By applying in situ uniaxial stress, we break the symmetry of this disorder-free, frustrated kagome system in a controlled manner yielding a linear increase of T_{N} with strain, in line with theoretical predictions for a distorted kagome lattice. In-plane strain of ≈1% triggers a sizable enhancement ΔT_{N}/T_{N}≈10% due to a release of frustration, demonstrating its pivotal role for magnetic order.
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Affiliation(s)
- Jierong Wang
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - M Spitaler
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - Y-S Su
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - K M Zoch
- Institute of Physics, Goethe-University Frankfurt, 60438 Frankfurt (Main), Germany
| | - C Krellner
- Institute of Physics, Goethe-University Frankfurt, 60438 Frankfurt (Main), Germany
| | - P Puphal
- Institute of Physics, Goethe-University Frankfurt, 60438 Frankfurt (Main), Germany
- Max-Planck-Institute for Solid State Research, 70569 Stuttgart, Germany
| | - S E Brown
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - A Pustogow
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
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4
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Noad HML, Ishida K, Li YS, Gati E, Stangier V, Kikugawa N, Sokolov DA, Nicklas M, Kim B, Mazin II, Garst M, Schmalian J, Mackenzie AP, Hicks CW. Giant lattice softening at a Lifshitz transition in Sr 2RuO 4. Science 2023; 382:447-450. [PMID: 37883549 DOI: 10.1126/science.adf3348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 09/16/2023] [Indexed: 10/28/2023]
Abstract
The interplay of electronic and structural degrees of freedom in solids is a topic of intense research. More than 60 years ago, Lifshitz discussed a counterintuitive possibility: lattice softening driven by conduction electrons at topological Fermi surface transitions. The effect that he predicted, however, was small and has not been convincingly observed. Using a piezo-based uniaxial pressure cell to tune the ultraclean metal strontium ruthenate while measuring the stress-strain relationship, we reveal a huge softening of the Young's modulus at a Lifshitz transition of a two-dimensional Fermi surface and show that it is indeed driven entirely by the conduction electrons of the relevant energy band.
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Affiliation(s)
- H M L Noad
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - K Ishida
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Y-S Li
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - E Gati
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - V Stangier
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - N Kikugawa
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0003, Japan
| | - D A Sokolov
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - M Nicklas
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - B Kim
- Department of Physics, Kunsan National University, Gunsan 54150, Korea
- Department of Physics, Kyungpook National University, Daegu 41566, Korea
| | - I I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA 22030, USA
| | - M Garst
- Institut für Theoretische Festkörperphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
- Institut für QuantenMaterialien und Technologien, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - J Schmalian
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
- Institut für QuantenMaterialien und Technologien, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - C W Hicks
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
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5
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Dashwood CD, Walker AH, Kwasigroch MP, Veiga LSI, Faure Q, Vale JG, Porter DG, Manuel P, Khalyavin DD, Orlandi F, Colin CV, Fabelo O, Krüger F, Perry RS, Johnson RD, Green AG, McMorrow DF. Strain control of a bandwidth-driven spin reorientation in Ca 3Ru 2O 7. Nat Commun 2023; 14:6197. [PMID: 37794061 PMCID: PMC10550943 DOI: 10.1038/s41467-023-41714-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 09/15/2023] [Indexed: 10/06/2023] Open
Abstract
The layered-ruthenate family of materials possess an intricate interplay of structural, electronic and magnetic degrees of freedom that yields a plethora of delicately balanced ground states. This is exemplified by Ca3Ru2O7, which hosts a coupled transition in which the lattice parameters jump, the Fermi surface partially gaps and the spins undergo a 90∘ in-plane reorientation. Here, we show how the transition is driven by a lattice strain that tunes the electronic bandwidth. We apply uniaxial stress to single crystals of Ca3Ru2O7, using neutron and resonant x-ray scattering to simultaneously probe the structural and magnetic responses. These measurements demonstrate that the transition can be driven by externally induced strain, stimulating the development of a theoretical model in which an internal strain is generated self-consistently to lower the electronic energy. We understand the strain to act by modifying tilts and rotations of the RuO6 octahedra, which directly influences the nearest-neighbour hopping. Our results offer a blueprint for uncovering the driving force behind coupled phase transitions, as well as a route to controlling them.
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Affiliation(s)
- C D Dashwood
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK.
| | - A H Walker
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK.
| | - M P Kwasigroch
- Department of Mathematics, University College London, London, WC1H 0AY, UK
- Trinity College, Cambridge, CB2 1TQ, UK
| | - L S I Veiga
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Q Faure
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
- Laboratoire León Brillouin, CEA, CNRS, Université Paris-Saclay, CEA-Saclay, 91191, Gif-sur-Yvette, France
| | - J G Vale
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - D G Porter
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - P Manuel
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - D D Khalyavin
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - F Orlandi
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - C V Colin
- Université Grenoble Alpes, CNRS, Institut Néel, 38000, Grenoble, France
| | - O Fabelo
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042, Grenoble, France
| | - F Krüger
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - R S Perry
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - R D Johnson
- Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - A G Green
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - D F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
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6
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Dong Z, Lee PA, Levitov LS. Signatures of Cooper pair dynamics and quantum-critical superconductivity in tunable carrier bands. Proc Natl Acad Sci U S A 2023; 120:e2305943120. [PMID: 37738298 PMCID: PMC10523641 DOI: 10.1073/pnas.2305943120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/21/2023] [Indexed: 09/24/2023] Open
Abstract
Different superconducting pairing mechanisms are markedly distinct in the underlying Cooper pair kinematics. Quantum-critical soft modes drive pairing interactions in which the pair scattering processes are highly collinear and can be classified into two categories: forward scattering and backscattering. Conversely, in conventional phonon mechanisms, Cooper pair scattering is of a generic noncollinear character. In this study, we present a method to discern the kinematic type by observing the evolution of superconductivity while adjusting the Fermi surface geometry. To demonstrate our approach, we utilize the recently reported phase diagrams of untwisted graphene multilayers. Our analysis connects the emergence of superconductivity at "ghost crossings" of Fermi surfaces in distinct valleys to the pair kinematics of a backscattering type. Together with the observed nonmonotonic behavior of superconductivity near its onset (sharp rise followed by a drop), it lends strong support to a particular quantum-critical superconductivity scenario in which pairing is driven by intervalley coherence fluctuations. These findings offer direct insights into the genesis of pairing in these systems, providing compelling evidence for the electron-electron interactions driving superconductivity. More broadly, our work highlights the potential of tuning bands via ghost crossings as a promising means of boosting superconductivity.
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Affiliation(s)
- Zhiyu Dong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Patrick A. Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Leonid S. Levitov
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
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7
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Curran PJ, Bending SJ, Gibbs AS, Mackenzie AP. The search for spontaneous edge currents in Sr 2RuO 4 mesa structures with controlled geometrical shapes. Sci Rep 2023; 13:12652. [PMID: 37542057 PMCID: PMC10403554 DOI: 10.1038/s41598-023-39590-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/27/2023] [Indexed: 08/06/2023] Open
Abstract
Scanning Hall microscopy has been used to search for spontaneous edge fields in geometrically shaped mesa structures etched into the ab surface of Sr2RuO4 single crystals in order to test recent theories of the direction of edge current flow as a function of facet orientation and band filling. We find no evidence for spontaneous edge fields in any of our mesa structures above our experimental noise floor of ± 25 mG. We do, however, observe pronounced vortex clustering at low fields and temperatures, consistent with the established semi-Meissner scenario whereby a long range attractive component to the vortex-vortex interaction arises due, for example, to the multiband nature of the superconductivity. We also see clear evidence for the formation of a square vortex lattice inside square mesa structures above 1.3 K. Our results are discussed in terms of recent relevant experimental results and theoretical predictions.
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Affiliation(s)
- P J Curran
- Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - S J Bending
- Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - A S Gibbs
- School of Chemistry, University of St. Andrews, St. Andrews, KY16 9ST, UK
| | - A P Mackenzie
- School of Physics and Astronomy, University of St. Andrews, St. Andrews, KY16 9SS, UK
- Max-Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
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8
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Yang PY, Noad HML, Barber ME, Kikugawa N, Sokolov DA, Mackenzie AP, Hicks CW. Probing Momentum-Dependent Scattering in Uniaxially Stressed Sr_{2}RuO_{4} through the Hall Effect. PHYSICAL REVIEW LETTERS 2023; 131:036301. [PMID: 37540856 DOI: 10.1103/physrevlett.131.036301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 06/22/2023] [Indexed: 08/06/2023]
Abstract
The largest Fermi surface sheet of the correlated metal Sr_{2}RuO_{4} can be driven through a Lifshitz transition between an electronlike and an open geometry by uniaxial stress applied along the [100] lattice direction. Here, we investigate the effect of this transition on the longitudinal resistivity ρ_{xx} and the Hall coefficient R_{H}. ρ_{xx}(T), when Sr_{2}RuO_{4} is tuned to this transition, is found to have a T^{2}logT form, as expected for a Fermi liquid tuned to a Lifshitz transition. R_{H} is found to become more negative as the Fermi surface transitions from an electronlike to an open geometry, opposite to general expectations from this change in topology. The magnitude of the change in R_{H} implies that scattering changes throughout the Brillouin zone, not just at the point in k space where the transition occurs. In a model of orbital-dependent scattering, the electron-electron scattering rate on sections of Fermi surface with xy orbital weight is found to decrease dramatically.
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Affiliation(s)
- Po-Ya Yang
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
| | - Hilary M L Noad
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
| | - Mark E Barber
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford, California 94305, USA
| | - Naoki Kikugawa
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0003, Japan
| | - Dmitry A Sokolov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187 Dresden, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
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9
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Guo Y, Qiu D, Shao M, Song J, Wang Y, Xu M, Yang C, Li P, Liu H, Xiong J. Modulations in Superconductors: Probes of Underlying Physics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209457. [PMID: 36504310 DOI: 10.1002/adma.202209457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/16/2022] [Indexed: 06/02/2023]
Abstract
The importance of modulations is elevated to an unprecedented level, due to the delicate conditions required to bring out exotic phenomena in quantum materials, such as topological materials, magnetic materials, and superconductors. Recently, state-of-the-art modulation techniques in material science, such as electric-double-layer transistor, piezoelectric-based strain apparatus, angle twisting, and nanofabrication, have been utilized in superconductors. They not only efficiently increase the tuning capability to the broader ranges but also extend the tuning dimensionality to unprecedented degrees of freedom, including quantum fluctuations of competing phases, electronic correlation, and phase coherence essential to global superconductivity. Here, for a comprehensive review, these techniques together with the established modulation methods, such as elemental substitution, annealing, and polarization-induced gating, are contextualized. Depending on the mechanism of each method, the modulations are categorized into stoichiometric manipulation, electrostatic gating, mechanical modulation, and geometrical design. Their recent advances are highlighted by applications in newly discovered superconductors, e.g., nickelates, Kagome metals, and magic-angle graphene. Overall, the review is to provide systematic modulations in emergent superconductors and serve as the coordinate for future investigations, which can stimulate researchers in superconductivity and other fields to perform various modulations toward a thorough understanding of quantum materials.
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Affiliation(s)
- Yehao Guo
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Dong Qiu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Mingxin Shao
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Jingyan Song
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yang Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Minyi Xu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Chao Yang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Peng Li
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Haiwen Liu
- Department of Physics, Beijing Normal University, Beijing, 100875, China
| | - Jie Xiong
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
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10
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Goodge BH, Geisler B, Lee K, Osada M, Wang BY, Li D, Hwang HY, Pentcheva R, Kourkoutis LF. Resolving the polar interface of infinite-layer nickelate thin films. NATURE MATERIALS 2023; 22:466-473. [PMID: 36973543 DOI: 10.1038/s41563-023-01510-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Nickel-based superconductors provide a long-awaited experimental platform to explore possible cuprate-like superconductivity. Despite similar crystal structure and d electron filling, however, superconductivity in nickelates has thus far only been stabilized in thin-film geometry, raising questions about the polar interface between substrate and thin film. Here we conduct a detailed experimental and theoretical study of the prototypical interface between Nd1-xSrxNiO2 and SrTiO3. Atomic-resolution electron energy loss spectroscopy in the scanning transmission electron microscope reveals the formation of a single intermediate Nd(Ti,Ni)O3 layer. Density functional theory calculations with a Hubbard U term show how the observed structure alleviates the polar discontinuity. We explore the effects of oxygen occupancy, hole doping and cation structure to disentangle the contributions of each for reducing interface charge density. Resolving the non-trivial interface structure will be instructive for future synthesis of nickelate films on other substrates and in vertical heterostructures.
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Affiliation(s)
- Berit H Goodge
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA.
| | - Benjamin Geisler
- Department of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg, Germany
| | - Kyuho Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Motoki Osada
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Bai Yang Wang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Danfeng Li
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA
- Department of Physics, City University of Hong Kong, Kowloon, Hong Kong
| | - Harold Y Hwang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Rossitza Pentcheva
- Department of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg, Germany
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA.
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11
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Kim D, Kim Y, Sohn B, Kim M, Kim B, Noh TW, Kim C. Electric Control of 2D Van Hove Singularity in Oxide Ultra-Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207188. [PMID: 36764325 DOI: 10.1002/adma.202207188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/02/2023] [Indexed: 05/17/2023]
Abstract
Divergent density of states (DOS) can induce extraordinary phenomena such as significant enhancement of superconductivity and unexpected phase transitions. Moreover, van Hove singularities (VHSs) lead to divergent DOS in 2D systems. Despite recent interest in VHSs, only a few controllable cases have been reported to date. In this work, by utilizing an atomically ultra-thin SrRuO3 film, the electronic structure of a 2D VHS is investigated with angle-resolved photoemission spectroscopy and transport properties are controlled. By applying electric fields with alkali metal deposition and ionic-liquid gating methods, the 2D VHS and the sign of the charge carrier are precisely controlled. Use of a tunable 2D VHS in an atomically flat oxide film could serve as a new strategy to realize infinite DOS near the Fermi level, thereby allowing efficient tuning of electric properties.
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Affiliation(s)
- Donghan Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Younsik Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Byungmin Sohn
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Minsoo Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Bongju Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
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12
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Abarca Morales E, Siemann GR, Zivanovic A, Murgatroyd PAE, Marković I, Edwards B, Hooley CA, Sokolov DA, Kikugawa N, Cacho C, Watson MD, Kim TK, Hicks CW, Mackenzie AP, King PDC. Hierarchy of Lifshitz Transitions in the Surface Electronic Structure of Sr_{2}RuO_{4} under Uniaxial Compression. PHYSICAL REVIEW LETTERS 2023; 130:096401. [PMID: 36930931 DOI: 10.1103/physrevlett.130.096401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
We report the evolution of the electronic structure at the surface of the layered perovskite Sr_{2}RuO_{4} under large in-plane uniaxial compression, leading to anisotropic B_{1g} strains of ϵ_{xx}-ϵ_{yy}=-0.9±0.1%. From angle-resolved photoemission, we show how this drives a sequence of Lifshitz transitions, reshaping the low-energy electronic structure and the rich spectrum of van Hove singularities that the surface layer of Sr_{2}RuO_{4} hosts. From comparison to tight-binding modeling, we find that the strain is accommodated predominantly by bond-length changes rather than modifications of octahedral tilt and rotation angles. Our study sheds new light on the nature of structural distortions at oxide surfaces, and how targeted control of these can be used to tune density of state singularities to the Fermi level, in turn paving the way to the possible realization of rich collective states at the Sr_{2}RuO_{4} surface.
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Affiliation(s)
- Edgar Abarca Morales
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Gesa-R Siemann
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Andela Zivanovic
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Philip A E Murgatroyd
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Igor Marković
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Brendan Edwards
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Chris A Hooley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Dmitry A Sokolov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - Naoki Kikugawa
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0003, Japan
| | - Cephise Cacho
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 ODE, United Kingdom
| | - Matthew D Watson
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 ODE, United Kingdom
| | - Timur K Kim
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 ODE, United Kingdom
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
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13
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Gong X, Autieri C, Zhou H, Ma J, Tang X, Zheng X, Ming X. In-gap states and strain-tuned band convergence in layered structure trivalent iridate K 0.75Na 0.25IrO 2. Phys Chem Chem Phys 2023; 25:6857-6866. [PMID: 36799367 DOI: 10.1039/d2cp04806j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Iridium oxides (iridates) provide a good platform to study the delicate interplay between spin-orbit coupling (SOC) interactions, electron correlation effects, Hund's coupling and lattice degrees of freedom. An overwhelming number of investigations primarily focus on tetravalent (Ir4+, 5d5) and pentavalent (Ir5+, 5d4) iridates, and far less attention has been paid to iridates with other valence states. Here, we pay our attention to a less-explored trivalent (Ir3+, 5d6) iridate, K0.75Na0.25IrO2, crystallizing in a triangular lattice with edge-sharing IrO6 octahedra and alkali metal ion intercalated [IrO2]- layers, offering a good platform to explore the interplay between different degrees of freedom. We theoretically determine the preferred occupied positions of the alkali metal ions from energetic viewpoints and reproduce the experimentally observed semiconducting behavior and nonmagnetic (NM) properties of K0.75Na0.25IrO2. The SOC interactions play a critical role in the band dispersion, resulting in NM Jeff = 0 states. More intriguingly, our electronic structure not only uncovers the presence of intrinsic in-gap states and nearly free electron character for the conduction band minimum, but also explains the abnormally low activation energy in K0.75Na0.25IrO2. Particularly, the band edge can be effectively modulated by mechanical strain, and the in-gap states feature enhanced band-convergence characteristics by 6% compressive strain, which will greatly enhance the electrical conductivity of K0.75Na0.25IrO2. The present work sheds new light on the unconventional electronic structures of trivalent iridates, indicating their promising application as a nanoelectronic and thermoelectric material, which will attract extensive interest and stimulate experimental works to further understand the unprecedented electronic structures and exploit potential applications of the triangular trivalent iridate.
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Affiliation(s)
- Xujia Gong
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Carmine Autieri
- International Research Centre Magtop, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Huanfu Zhou
- Key Lab of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, School of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Jiafeng Ma
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Xin Tang
- Key Lab of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, School of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Xiaojun Zheng
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Xing Ming
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
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14
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Qi Y, Sadi MA, Hu D, Zheng M, Wu Z, Jiang Y, Chen YP. Recent Progress in Strain Engineering on Van der Waals 2D Materials: Tunable Electrical, Electrochemical, Magnetic, and Optical Properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205714. [PMID: 35950446 DOI: 10.1002/adma.202205714] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/01/2022] [Indexed: 06/15/2023]
Abstract
Strain engineering is a promising way to tune the electrical, electrochemical, magnetic, and optical properties of 2D materials, with the potential to achieve high-performance 2D-material-based devices ultimately. This review discusses the experimental and theoretical results from recent advances in the strain engineering of 2D materials. Some novel methods to induce strain are summarized and then the tunable electrical and optical/optoelectronic properties of 2D materials via strain engineering are highlighted, including particularly the previously less-discussed strain tuning of superconducting, magnetic, and electrochemical properties. Also, future perspectives of strain engineering are given for its potential applications in functional devices. The state of the survey presents the ever-increasing advantages and popularity of strain engineering for tuning properties of 2D materials. Suggestions and insights for further research and applications in optical, electronic, and spintronic devices are provided.
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Affiliation(s)
- Yaping Qi
- Department of Engineering Science, Faculty of Innovation Engineering, Macau University of Science and Technology, Av. Wai Long, Macao SAR, China
| | - Mohammad A Sadi
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Dan Hu
- Department of Engineering Science, Faculty of Innovation Engineering, Macau University of Science and Technology, Av. Wai Long, Macao SAR, China
| | - Ming Zheng
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China
| | - Zhenping Wu
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Yucheng Jiang
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou, Jiangsu, 215009, P. R. China
| | - Yong P Chen
- Department of Engineering Science, Faculty of Innovation Engineering, Macau University of Science and Technology, Av. Wai Long, Macao SAR, China
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Department of Physics and Astronomy and Birck Nanotechnology Center and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, 47907, USA
- Institute of Physics and Astronomy and Villum Center for Hybrid Quantum Materials and Devices, Aarhus University, Aarhus-C, 8000, Denmark
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15
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Kim B, Khmelevskyi S, Franchini C, Mazin II. Suppressed Fluctuations as the Origin of the Static Magnetic Order in Strained Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2023; 130:026702. [PMID: 36706403 DOI: 10.1103/physrevlett.130.026702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/04/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Combining first-principles density-functional calculations and Moriya's self-consistent renormalization theory, we explain the recently reported counterintuitive appearance of an ordered magnetic state in uniaxially strained Sr_{2}RuO_{4} beyond the Lifshitz transition. We show that strain weakens the quantum spin fluctuations, which destroy the static order, more strongly than the tendency to magnetism. A different rate of decrease of the spin fluctuations vs magnetic stabilization energy promotes the onset of a static magnetic order beyond a critical strain.
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Affiliation(s)
- Bongjae Kim
- Department of Physics, Kunsan National University, Gunsan 54150, Korea
| | - Sergii Khmelevskyi
- Center for Computational Materials Science, Institute for Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Cesare Franchini
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna A-1090, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
| | - I I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia 22030, USA
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16
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Simutis G, Bollhalder A, Zolliker M, Küspert J, Wang Q, Das D, Van Leeuwen F, Ivashko O, Gutowski O, Philippe J, Kracht T, Glaevecke P, Adachi T, V Zimmermann M, Van Petegem S, Luetkens H, Guguchia Z, Chang J, Sassa Y, Bartkowiak M, Janoschek M. In situ uniaxial pressure cell for x-ray and neutron scattering experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:013906. [PMID: 36725613 DOI: 10.1063/5.0114892] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/24/2022] [Indexed: 06/18/2023]
Abstract
We present an in situ uniaxial pressure device optimized for small angle x-ray and neutron scattering experiments at low-temperatures and high magnetic fields. A stepper motor generates force, which is transmitted to the sample via a rod with an integrated transducer that continuously monitors the force. The device has been designed to generate forces up to 200 N in both compressive and tensile configurations, and a feedback control allows operating the system in a continuous-pressure mode as the temperature is changed. The uniaxial pressure device can be used for various instruments and multiple cryostats through simple and exchangeable adapters. It is compatible with multiple sample holders, which can be easily changed depending on the sample properties and the desired experiment and allow rapid sample changes.
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Affiliation(s)
- G Simutis
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Bollhalder
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Zolliker
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Küspert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Q Wang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - D Das
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - F Van Leeuwen
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - O Ivashko
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - O Gutowski
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - J Philippe
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Kracht
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - P Glaevecke
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - T Adachi
- Department of Engineering and Applied Sciences, Sophia University, Chiyoda, Tokyo, 102-8554, Japan
| | - M V Zimmermann
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - S Van Petegem
- Structure and Mechanics of Advanced Materials, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - H Luetkens
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Z Guguchia
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Y Sassa
- Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - M Bartkowiak
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Janoschek
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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17
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Giant stress response of terahertz magnons in a spin-orbit Mott insulator. Nat Commun 2022; 13:6674. [DOI: 10.1038/s41467-022-34375-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
AbstractMagnonic devices operating at terahertz frequencies offer intriguing prospects for high-speed electronics with minimal energy dissipation However, guiding and manipulating terahertz magnons via external parameters present formidable challenges. Here we report the results of magnetic Raman scattering experiments on the antiferromagnetic spin-orbit Mott insulator Sr2IrO4 under uniaxial stress. We find that the energies of zone-center magnons are extremely stress sensitive: lattice strain of 0.1% increases the magnon energy by 40%. The magnon response is symmetric with respect to the sign of the applied stress (tensile or compressive), but depends strongly on its direction in the IrO2 planes. A theory based on coupling of the spin-orbit-entangled iridium magnetic moments to lattice distortions provides a quantitative explanation of the Raman data and a comprehensive framework for the description of magnon-lattice interactions in magnets with strong spin-orbit coupling. The possibility to efficiently manipulate the propagation of terahertz magnons via external stress opens up multifold design options for reconfigurable magnonic devices.
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18
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Jerzembeck F, Røising HS, Steppke A, Rosner H, Sokolov DA, Kikugawa N, Scaffidi T, Simon SH, Mackenzie AP, Hicks CW. The superconductivity of Sr 2RuO 4 under c-axis uniaxial stress. Nat Commun 2022; 13:4596. [PMID: 35933412 PMCID: PMC9357014 DOI: 10.1038/s41467-022-32177-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/19/2022] [Indexed: 11/15/2022] Open
Abstract
Applying in-plane uniaxial pressure to strongly correlated low-dimensional systems has been shown to tune the electronic structure dramatically. For example, the unconventional superconductor Sr2RuO4 can be tuned through a single Van Hove point, resulting in strong enhancement of both Tc and Hc2. Out-of-plane (c axis) uniaxial pressure is expected to tune the quasi-two-dimensional structure even more strongly, by pushing it towards two Van Hove points simultaneously. Here, we achieve a record uniaxial stress of 3.2 GPa along the c axis of Sr2RuO4. Hc2 increases, as expected for increasing density of states, but unexpectedly Tc falls. As a first attempt to explain this result, we present three-dimensional calculations in the weak interaction limit. We find that within the weak-coupling framework there is no single order parameter that can account for the contrasting effects of in-plane versus c-axis uniaxial stress, which makes this new result a strong constraint on theories of the superconductivity of Sr2RuO4. In the superconductor Sr2RuO4, in-plane strain is known to enhance both the superconducting transition temperature Tc and upper critical field Hc2, but the effect of out-of-plane strain has not been studied. Here, the authors find that Hc2 is enhanced under out-of-plane strain, but Tc unexpectedly decreases.
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Affiliation(s)
- Fabian Jerzembeck
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany.
| | - Henrik S Røising
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, SE-106 91, Stockholm, Sweden
| | - Alexander Steppke
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany
| | - Helge Rosner
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany
| | - Dmitry A Sokolov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany
| | - Naoki Kikugawa
- National Institute for Materials Science, Tsukuba, 305-0003, Japan
| | - Thomas Scaffidi
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.,Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Steven H Simon
- Rudolf Peierls Center for Theoretical Physics, Oxford, OX1 3PU, UK
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany. .,Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews, KY16 9SS, UK.
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str 40, 01187, Dresden, Germany. .,School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK.
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19
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Abstract
One of the main developments in unconventional superconductivity in the past two decades has been the discovery that most unconventional superconductors form phase diagrams that also contain other strongly correlated states. Many systems of interest are therefore close to more than one instability, and tuning between the resultant ordered phases is the subject of intense research1. In recent years, uniaxial pressure applied using piezoelectric-based devices has been shown to be a particularly versatile new method of tuning2,3, leading to experiments that have advanced our understanding of the fascinating unconventional superconductor Sr2RuO4 (refs. 4–9). Here we map out its phase diagram using high-precision measurements of the elastocaloric effect in what we believe to be the first such study including both the normal and the superconducting states. We observe a strong entropy quench on entering the superconducting state, in excellent agreement with a model calculation for pairing at the Van Hove point, and obtain a quantitative estimate of the entropy change associated with entry to a magnetic state that is observed in proximity to the superconductivity. The phase diagram is intriguing both for its similarity to those seen in other families of unconventional superconductors and for extra features unique, so far, to Sr2RuO4. The phase diagram of the unconventional superconductor Sr2RuO4 in both normal and superconducting states is mapped out using high-precision measurements of the elastocaloric effect, showing similarities to other unconventional superconductors as well as unique features.
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20
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Najev A, Hameed S, Gautreau D, Wang Z, Joe J, Požek M, Birol T, Fernandes RM, Greven M, Pelc D. Uniaxial Strain Control of Bulk Ferromagnetism in Rare-Earth Titanates. PHYSICAL REVIEW LETTERS 2022; 128:167201. [PMID: 35522519 DOI: 10.1103/physrevlett.128.167201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 10/26/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
The perovskite rare-earth titanates are model Mott insulators with magnetic ground states that are very sensitive to structural distortions. These distortions couple strongly to the orbital degrees of freedom and, in principle, it should be possible to tune the superexchange and the magnetic transition with strain. We investigate the representative system (Y,La,Ca)TiO_{3}, which exhibits low crystallographic symmetry and no structural instabilities. From magnetic susceptibility measurements of the Curie temperature, we demonstrate direct, reversible, and continuous control of ferromagnetism by influencing the TiO_{6} octahedral tilts and rotations with uniaxial strain. The relative change in T_{C} as a function of strain is well described by ab initio calculations, which provides detailed understanding of the complex interactions among structural, orbital, and magnetic properties in rare-earth titanates. The demonstrated manipulation of octahedral distortions opens up far-reaching possibilities for investigations of electron-lattice coupling, competing ground states, and magnetic quantum phase transitions in a wide range of quantum materials.
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Affiliation(s)
- A Najev
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, HR-10000 Zagreb, Croatia
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - S Hameed
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - D Gautreau
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Z Wang
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - J Joe
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - M Požek
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, HR-10000 Zagreb, Croatia
| | - T Birol
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - M Greven
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - D Pelc
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, HR-10000 Zagreb, Croatia
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
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21
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Kinjo K, Manago M, Kitagawa S, Mao ZQ, Yonezawa S, Maeno Y, Ishida K. Superconducting spin smecticity evidencing the Fulde-Ferrell-Larkin-Ovchinnikov state in Sr 2RuO 4. Science 2022; 376:397-400. [PMID: 35446631 DOI: 10.1126/science.abb0332] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Translational symmetry breaking is antagonistic to static fluidity but can be realized in superconductors, which host a quantum-mechanical coherent fluid formed by electron pairs. A peculiar example of such a state is the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, induced by a time-reversal symmetry-breaking magnetic field applied to spin-singlet superconductors. This state is intrinsically accompanied by the superconducting spin smecticity, spin density-modulated fluidity with spontaneous translational-symmetry breaking. Detection of such spin smecticity provides unambiguous evidence for the FFLO state, but its observation has been challenging. Here, we report the characteristic "double-horn" nuclear magnetic resonance spectrum in the layered superconductor Sr2RuO4 near its upper critical field, indicating the spatial sinusoidal modulation of spin density that is consistent with superconducting spin smecticity. Our work reveals that Sr2RuO4 provides a versatile platform for studying FFLO physics.
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Affiliation(s)
- K Kinjo
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - M Manago
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | | | - Z Q Mao
- Department of Physics, Pennsylvania State University, State College, PA, USA
| | - S Yonezawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Y Maeno
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - K Ishida
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
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22
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Hameed S, Pelc D, Anderson ZW, Klein A, Spieker RJ, Yue L, Das B, Ramberger J, Lukas M, Liu Y, Krogstad MJ, Osborn R, Li Y, Leighton C, Fernandes RM, Greven M. Enhanced superconductivity and ferroelectric quantum criticality in plastically deformed strontium titanate. NATURE MATERIALS 2022; 21:54-61. [PMID: 34608284 DOI: 10.1038/s41563-021-01102-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach using irreversible, plastic deformation of single crystals. We show that compressive plastic deformation induces low-dimensional superconductivity well above the superconducting transition temperature (Tc) of undeformed SrTiO3, with evidence of possible superconducting correlations at temperatures two orders of magnitude above the bulk Tc. The enhanced superconductivity is correlated with the appearance of self-organized dislocation structures, as revealed by diffuse neutron and X-ray scattering. We also observe deformation-induced signatures of quantum-critical ferroelectric fluctuations and inhomogeneous ferroelectric order using Raman scattering. Our results suggest that strain surrounding the self-organized dislocation structures induces local ferroelectricity and quantum-critical dynamics that strongly influence Tc, consistent with a theory of superconductivity enhanced by soft polar fluctuations. Our results demonstrate the potential of plastic deformation and dislocation engineering for the manipulation of electronic properties of quantum materials.
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Affiliation(s)
- S Hameed
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - D Pelc
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA.
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia.
| | - Z W Anderson
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - A Klein
- Department of Physics, Faculty of Natural Sciences, Ariel University, Ariel, Israel
| | - R J Spieker
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - L Yue
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - B Das
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - J Ramberger
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - M Lukas
- Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia
| | - Y Liu
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - M J Krogstad
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - R Osborn
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Y Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - C Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - M Greven
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA.
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23
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Olde Olthof LAB, Johnsen LG, Robinson JWA, Linder J. Controllable Enhancement of p-Wave Superconductivity via Magnetic Coupling to a Conventional Superconductor. PHYSICAL REVIEW LETTERS 2021; 127:267001. [PMID: 35029472 DOI: 10.1103/physrevlett.127.267001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
Unconventional superconductors are of high interest due to their rich physics, a topical example being topological edge states associated with p-wave superconductivity. A practical obstacle in studying such systems is the very low critical temperature T_{c} that is required to realize a p-wave superconducting phase in a material. We predict that the T_{c} of an intrinsic p-wave superconductor can be significantly enhanced by coupling to a conventional s-wave or d-wave superconductor with a higher critical temperature via an atomically thin ferromagnetic (F) layer. We show that this T_{c} boost is tunable via the direction of the magnetization in F. Moreover, we show that the enhancement in T_{c} can also be achieved using the Zeeman effect of an external magnetic field. Our findings provide a way to increase T_{c} in p-wave superconductors in a controllable way and make the exotic physics associated with such materials more easily accessible experimentally.
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Affiliation(s)
- Linde A B Olde Olthof
- Department of Materials Science & Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
| | - Lina G Johnsen
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Jason W A Robinson
- Department of Materials Science & Metallurgy, University of Cambridge, CB3 0FS Cambridge, United Kingdom
| | - Jacob Linder
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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24
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Kim JM, Haque MF, Hsieh EY, Nahid SM, Zarin I, Jeong KY, So JP, Park HG, Nam S. Strain Engineering of Low-Dimensional Materials for Emerging Quantum Phenomena and Functionalities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2107362. [PMID: 34866241 DOI: 10.1002/adma.202107362] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/11/2021] [Indexed: 06/13/2023]
Abstract
Recent discoveries of exotic physical phenomena, such as unconventional superconductivity in magic-angle twisted bilayer graphene, dissipationless Dirac fermions in topological insulators, and quantum spin liquids, have triggered tremendous interest in quantum materials. The macroscopic revelation of quantum mechanical effects in quantum materials is associated with strong electron-electron correlations in the lattice, particularly where materials have reduced dimensionality. Owing to the strong correlations and confined geometry, altering atomic spacing and crystal symmetry via strain has emerged as an effective and versatile pathway for perturbing the subtle equilibrium of quantum states. This review highlights recent advances in strain-tunable quantum phenomena and functionalities, with particular focus on low-dimensional quantum materials. Experimental strategies for strain engineering are first discussed in terms of heterogeneity and elastic reconfigurability of strain distribution. The nontrivial quantum properties of several strain-quantum coupled platforms, including 2D van der Waals materials and heterostructures, topological insulators, superconducting oxides, and metal halide perovskites, are next outlined, with current challenges and future opportunities in quantum straintronics followed. Overall, strain engineering of quantum phenomena and functionalities is a rich field for fundamental research of many-body interactions and holds substantial promise for next-generation electronics capable of ultrafast, dissipationless, and secure information processing and communications.
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Affiliation(s)
- Jin Myung Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Md Farhadul Haque
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ezekiel Y Hsieh
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Shahriar Muhammad Nahid
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ishrat Zarin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Kwang-Yong Jeong
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- Department of Physics, Jeju National University, Jeju, 63243, Republic of Korea
| | - Jae-Pil So
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
| | - Hong-Gyu Park
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, 02841, Republic of Korea
| | - SungWoo Nam
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Mechanical and Aerospace Engineering, University of California Irvine, Irvine, CA, 92697, USA
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25
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Fittipaldi R, Hartmann R, Mercaldo MT, Komori S, Bjørlig A, Kyung W, Yasui Y, Miyoshi T, Olde Olthof LAB, Palomares Garcia CM, Granata V, Keren I, Higemoto W, Suter A, Prokscha T, Romano A, Noce C, Kim C, Maeno Y, Scheer E, Kalisky B, Robinson JWA, Cuoco M, Salman Z, Vecchione A, Di Bernardo A. Unveiling unconventional magnetism at the surface of Sr 2RuO 4. Nat Commun 2021; 12:5792. [PMID: 34608149 PMCID: PMC8490454 DOI: 10.1038/s41467-021-26020-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/14/2021] [Indexed: 11/09/2022] Open
Abstract
Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr2RuO4, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr2RuO4 is still ongoing, a deeper understanding of the Sr2RuO4 normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr2RuO4 in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr2RuO4 surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.
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Affiliation(s)
- R Fittipaldi
- CNR-SPIN, c/o University of Salerno, I-84084, Fisciano, Salerno, Italy.,Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - R Hartmann
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - M T Mercaldo
- Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - S Komori
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.,Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - A Bjørlig
- Department of Physics, Bar Ilan University, Ramat Gan, 5920002, Israel
| | - W Kyung
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Y Yasui
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.,RIKEN, Centre for Emergent Matter Science, Saitama, 351-0198, Japan
| | - T Miyoshi
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - L A B Olde Olthof
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - C M Palomares Garcia
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - V Granata
- Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - I Keren
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen, PSI, Switzerland.,The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - W Higemoto
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - A Suter
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen, PSI, Switzerland
| | - T Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen, PSI, Switzerland
| | - A Romano
- CNR-SPIN, c/o University of Salerno, I-84084, Fisciano, Salerno, Italy.,Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - C Noce
- CNR-SPIN, c/o University of Salerno, I-84084, Fisciano, Salerno, Italy.,Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - C Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Y Maeno
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - E Scheer
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - B Kalisky
- Department of Physics, Bar Ilan University, Ramat Gan, 5920002, Israel
| | - J W A Robinson
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - M Cuoco
- CNR-SPIN, c/o University of Salerno, I-84084, Fisciano, Salerno, Italy. .,Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy.
| | - Z Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen, PSI, Switzerland.
| | - A Vecchione
- CNR-SPIN, c/o University of Salerno, I-84084, Fisciano, Salerno, Italy.,Dipartimento di Fisica "E.R. Caianiello", University of Salerno, I-84084, Fisciano, Salerno, Italy
| | - A Di Bernardo
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany.
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26
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Multiplicity, Parity and Angular Momentum of a Cooper Pair in Unconventional Superconductors of D4h Symmetry: Sr2RuO4 and Fe-Pnictide Materials. Symmetry (Basel) 2021. [DOI: 10.3390/sym13081435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Sr2RuO4 and Fe-pnictide superconductors belong to the same point group symmetry D4h. Many experimental data confirm odd pairs in Sr2RuO4 and even pairs in Fe-pnictides, but opposite conclusions also exist. Recent NMR results of Pustogow et al., which revealed even Cooper pairs in Sr2RuO4, require reconsideration of symmetry treatment of its SOP (superconducting order parameter). In the present work making use of the Mackey–Bradley theorem on symmetrized squares, a group theoretical investigation of possible pairing states in D4h symmetry is performed. It is obtained for I4/mmm , i.e., space group of Sr2RuO4, that triplet pairs with even spatial parts are possible in kz direction and in points M and Y. For the two latter cases pairing of equivalent electrons with nonzero total momentum is proposed. In P4/nmm space group of Fe- pnictides in point M, even and odd pairs are possible for singlet and triplet cases. It it shown that even and odd chiral states with angular momentum projection m=±1 have nodes in vertical planes, but Eg is nodal , whereas Eu is nodeless in the basal plane. It is also shown that the widely accepted assertion that the parity of angular momentum value is directly connected with the spatial parity of a pair is not valid in a space-group approach to the wavefunction of a Cooper pair.
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27
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King PDC. Controlling topology with strain. NATURE MATERIALS 2021; 20:1046-1047. [PMID: 34321651 DOI: 10.1038/s41563-021-01043-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK.
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28
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Grinenko V, Das D, Gupta R, Zinkl B, Kikugawa N, Maeno Y, Hicks CW, Klauss HH, Sigrist M, Khasanov R. Unsplit superconducting and time reversal symmetry breaking transitions in Sr 2RuO 4 under hydrostatic pressure and disorder. Nat Commun 2021; 12:3920. [PMID: 34168141 PMCID: PMC8225887 DOI: 10.1038/s41467-021-24176-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/01/2021] [Indexed: 11/23/2022] Open
Abstract
There is considerable evidence that the superconducting state of Sr2RuO4 breaks time reversal symmetry. In the experiments showing time reversal symmetry breaking, its onset temperature, TTRSB, is generally found to match the critical temperature, Tc, within resolution. In combination with evidence for even parity, this result has led to consideration of a dxz ± idyz order parameter. The degeneracy of the two components of this order parameter is protected by symmetry, yielding TTRSB = Tc, but it has a hard-to-explain horizontal line node at kz = 0. Therefore, s ± id and d ± ig order parameters are also under consideration. These avoid the horizontal line node, but require tuning to obtain TTRSB ≈ Tc. To obtain evidence distinguishing these two possible scenarios (of symmetry-protected versus accidental degeneracy), we employ zero-field muon spin rotation/relaxation to study pure Sr2RuO4 under hydrostatic pressure, and Sr1.98La0.02RuO4 at zero pressure. Both hydrostatic pressure and La substitution alter Tc without lifting the tetragonal lattice symmetry, so if the degeneracy is symmetry-protected, TTRSB should track changes in Tc, while if it is accidental, these transition temperatures should generally separate. We observe TTRSB to track Tc, supporting the hypothesis of dxz ± idyz order.
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Affiliation(s)
- Vadim Grinenko
- Institute for Solid State and Materials Physics, Technische Universität Dresden, Dresden, Germany.
- Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, Dresden, Germany.
| | - Debarchan Das
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland
| | - Ritu Gupta
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland
| | - Bastian Zinkl
- Institute for Theoretical Physics, ETH Zurich, Zurich, Switzerland
| | - Naoki Kikugawa
- National Institute for Materials Science, Tsukuba, Japan
| | | | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham, UK
| | - Hans-Henning Klauss
- Institute for Solid State and Materials Physics, Technische Universität Dresden, Dresden, Germany
| | - Manfred Sigrist
- Institute for Theoretical Physics, ETH Zurich, Zurich, Switzerland.
| | - Rustem Khasanov
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland.
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29
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Chronister A, Pustogow A, Kikugawa N, Sokolov DA, Jerzembeck F, Hicks CW, Mackenzie AP, Bauer ED, Brown SE. Evidence for even parity unconventional superconductivity in Sr 2RuO 4. Proc Natl Acad Sci U S A 2021; 118:e2025313118. [PMID: 34161272 PMCID: PMC8237678 DOI: 10.1073/pnas.2025313118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unambiguous identification of the superconducting order parameter symmetry in [Formula: see text] has remained elusive for more than a quarter century. While a chiral p-wave ground state analogue to superfluid 3He-A was ruled out only very recently, other proposed triplet-pairing scenarios are still viable. Establishing the condensate magnetic susceptibility reveals a sharp distinction between even-parity (singlet) and odd-parity (triplet) pairing since the superconducting condensate is magnetically polarizable only in the latter case. Here field-dependent 17O Knight shift measurements, being sensitive to the spin polarization, are compared to previously reported specific heat measurements for the purpose of distinguishing the condensate contribution from that due to quasiparticles. We conclude that the shift results can be accounted for entirely by the expected field-induced quasiparticle response. An upper bound for the condensate magnetic response of <10% of the normal state susceptibility is sufficient to exclude all purely odd-parity candidates.
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Affiliation(s)
- Aaron Chronister
- Department of Physics & Astronomy, University of California, Los Angeles, CA 90095;
| | - Andrej Pustogow
- Department of Physics & Astronomy, University of California, Los Angeles, CA 90095;
| | - Naoki Kikugawa
- Cryogenic Center for Liquid Hydrogen and Materials Science, National Institute for Materials Science, Tsukuba 305-0003, Japan
| | - Dmitry A Sokolov
- Physics of Quantum Materials Department, Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Fabian Jerzembeck
- Physics of Quantum Materials Department, Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Clifford W Hicks
- Physics of Quantum Materials Department, Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Andrew P Mackenzie
- Physics of Quantum Materials Department, Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Eric D Bauer
- Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Stuart E Brown
- Department of Physics & Astronomy, University of California, Los Angeles, CA 90095;
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30
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King PDC, Picozzi S, Egdell RG, Panaccione G. Angle, Spin, and Depth Resolved Photoelectron Spectroscopy on Quantum Materials. Chem Rev 2021; 121:2816-2856. [PMID: 33346644 DOI: 10.1021/acs.chemrev.0c00616] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of X-ray based electron spectroscopies in determining chemical, electronic, and magnetic properties of solids has been well-known for several decades. A powerful approach is angle-resolved photoelectron spectroscopy, whereby the kinetic energy and angle of photoelectrons emitted from a sample surface are measured. This provides a direct measurement of the electronic band structure of crystalline solids. Moreover, it yields powerful insights into the electronic interactions at play within a material and into the control of spin, charge, and orbital degrees of freedom, central pillars of future solid state science. With strong recent focus on research of lower-dimensional materials and modified electronic behavior at surfaces and interfaces, angle-resolved photoelectron spectroscopy has become a core technique in the study of quantum materials. In this review, we provide an introduction to the technique. Through examples from several topical materials systems, including topological insulators, transition metal dichalcogenides, and transition metal oxides, we highlight the types of information which can be obtained. We show how the combination of angle, spin, time, and depth-resolved experiments are able to reveal "hidden" spectral features, connected to semiconducting, metallic and magnetic properties of solids, as well as underlining the importance of dimensional effects in quantum materials.
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Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche, CNR-SPIN, Via dei Vestini 31, Chieti 66100, Italy
| | - Russell G Egdell
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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31
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Li YS, Kikugawa N, Sokolov DA, Jerzembeck F, Gibbs AS, Maeno Y, Hicks CW, Schmalian J, Nicklas M, Mackenzie AP. High-sensitivity heat-capacity measurements on Sr 2RuO 4 under uniaxial pressure. Proc Natl Acad Sci U S A 2021; 118:e2020492118. [PMID: 33653958 PMCID: PMC7958258 DOI: 10.1073/pnas.2020492118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/13/2021] [Indexed: 11/18/2022] Open
Abstract
A key question regarding the unconventional superconductivity of [Formula: see text] remains whether the order parameter is single- or two-component. Under a hypothesis of two-component superconductivity, uniaxial pressure is expected to lift their degeneracy, resulting in a split transition. The most direct and fundamental probe of a split transition is heat capacity. Here, we report measurement of heat capacity of samples subject to large and highly homogeneous uniaxial pressure. We place an upper limit on the heat-capacity signature of any second transition of a few percent of that of the primary superconducting transition. The normalized jump in heat capacity, [Formula: see text], grows smoothly as a function of uniaxial pressure, favoring order parameters which are allowed to maximize in the same part of the Brillouin zone as the well-studied van Hove singularity. Thanks to the high precision of our measurements, these findings place stringent constraints on theories of the superconductivity of [Formula: see text].
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Affiliation(s)
- You-Sheng Li
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Naoki Kikugawa
- National Institute for Materials Science, Tsukuba 305-0003, Japan
| | - Dmitry A Sokolov
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Fabian Jerzembeck
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Alexandra S Gibbs
- ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Yoshiteru Maeno
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Jörg Schmalian
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
- Institut für Quantenmaterialien und Technologien, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - Michael Nicklas
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany;
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany;
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
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32
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McCollam A, Fu M, Julian SR. Lifshitz transition underlying the metamagnetic transition of UPt 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:075804. [PMID: 33142270 DOI: 10.1088/1361-648x/abc729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Comparing quantum oscillation measurements, dc magnetoresistance measurements, and Fermi surfaces obtained from LDA calculations, we argue that the metamagnetic transition of UPt3, which occurs at an applied field μ ◦ H M ∼ 20 T, coincides with a Lifshitz transition at which an open orbit on the band 2 hole-like Fermi surface becomes closed for one spin direction. At low field, proximity of the Fermi energy to this particular van Hove singularity may have implications for the superconducting pairing potential of UPt3. In our picture the magnetization comes from non-linear spin-splitting of the heavy fermion bands. In support of this, we show that the non-linear field dependence of a particular quantum oscillation frequency can be fitted by assuming that the corresponding extremal Fermi surface area is proportional to the magnetization. In addition, below H M , we find in our LDA calculations a new, non-central orbit on band 1, whose non-linear behaviour explains a field-dependent frequency recently observed in magnetoacoustic quantum oscillation measurements.
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Affiliation(s)
- A McCollam
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Mingxuan Fu
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - S R Julian
- Department of Physics, University of Toronto, Toronto, M5S 1A7, Canada
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33
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Electronic Structure Correspondence of Singlet-Triplet Scale Separation in Strained Sr2RuO4. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11020508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
At a temperature of roughly 1 K, Sr2RuO4 undergoes a transition from a normal Fermi liquid to a superconducting phase. Even while the former is relatively simple and well understood, the superconducting state has not even been understood after 25 years of study. More recently, it has been found that critical temperatures can be enhanced by the application of uniaxial strain, up to a critical strain, after which it falls off. In this work, we take an “instability” approach and seek divergences in susceptibilities. This provides an unbiased way to distinguish tendencies to competing ground states. We show that in the unstrained compound, the singlet and triplet instabilities of the normal Fermi liquid phase are closely spaced. Under uniaxial strain, electrons residing on all orbitals contributing to the Fermiology become more coherent, while the electrons of the Ru-dxy character become heavier, and the electrons of the Ru-dxz,yz characters become lighter. In the process, Im χ(q,ω) increases rapidly around q = (0.3,0.3,0)2π/a and q = (0.5,0.25,0)2π/a, while it gets suppressed at all other commensurate vectors, in particular at q = 0, which is essential for spin-triplet superconductivity. We observe that the magnetic anisotropy under strain drops smoothly, which is concomitant with the increment in singlet instability. Thus, the triplet superconducting instability remains the lagging instability of the system, and the singlet instability enhances under strain, leading to a large energy-scale separation between these competing instabilities. However, since this happens even without spin-orbit coupling, we believe it is primarily the enhancement in the spin fluctuation glue around quasi-anti-ferromagnetic vectors that drives the Cooper pairing instead of the magnetic anisotropy. At large strain, an instability to a spin density wave overtakes the superconducting one. The analysis relies on a high-fidelity, ab initio description of the one-particle properties and two-particle susceptibilities, based on the quasiparticle self-consistent GW approximation augmented by dynamical mean field theory. This approach is described and its high fidelity confirmed by comparing to observed one- and two-particle properties.
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34
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Ruf JP, Paik H, Schreiber NJ, Nair HP, Miao L, Kawasaki JK, Nelson JN, Faeth BD, Lee Y, Goodge BH, Pamuk B, Fennie CJ, Kourkoutis LF, Schlom DG, Shen KM. Strain-stabilized superconductivity. Nat Commun 2021; 12:59. [PMID: 33397949 PMCID: PMC7782483 DOI: 10.1038/s41467-020-20252-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/19/2020] [Indexed: 11/09/2022] Open
Abstract
Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches. Here, we report the transmutation of a normal metal into a superconductor through the application of epitaxial strain. We demonstrate that synthesizing RuO2 thin films on (110)-oriented TiO2 substrates enhances the density of states near the Fermi level, which stabilizes superconductivity under strain, and suggests that a promising strategy to create new transition-metal superconductors is to apply judiciously chosen anisotropic strains that redistribute carriers within the low-energy manifold of d orbitals.
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Affiliation(s)
- J P Ruf
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA.
| | - H Paik
- Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials, Cornell University, Ithaca, NY, 14853, USA.,Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - N J Schreiber
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - H P Nair
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - L Miao
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA
| | - J K Kawasaki
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA.,Department of Materials Science and Engineering, University of Wisconsin, Madison, WI, 53706, USA
| | - J N Nelson
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA
| | - B D Faeth
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA.,Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials, Cornell University, Ithaca, NY, 14853, USA
| | - Y Lee
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA
| | - B H Goodge
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - B Pamuk
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - C J Fennie
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - L F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - D G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA.,Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, Berlin, 12489, Germany
| | - K M Shen
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA. .,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA.
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35
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Wiecki P, Haghighirad AA, Weber F, Merz M, Heid R, Böhmer AE. Dominant In-Plane Symmetric Elastoresistance in CsFe_{2}As_{2}. PHYSICAL REVIEW LETTERS 2020; 125:187001. [PMID: 33196224 DOI: 10.1103/physrevlett.125.187001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/15/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
We study the elastoresistance of the highly correlated material CsFe_{2}As_{2} in all symmetry channels. Neutralizing its thermal expansion by means of a piezoelectric-based strain cell is demonstrated to be essential. The elastoresistance response in the in-plane symmetric channel is found to be large, while the response in the symmetry-breaking channels is weaker and provides no evidence for a divergent nematic susceptibility. Rather, our results can be interpreted naturally within the framework of a coherence-incoherence crossover, where the low-temperature coherent state is sensitively tuned by the in-plane atomic distances.
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Affiliation(s)
- P Wiecki
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
| | - A-A Haghighirad
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
| | - F Weber
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
| | - M Merz
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
| | - R Heid
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
| | - A E Böhmer
- Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
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36
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Li YS, Borth R, Hicks CW, Mackenzie AP, Nicklas M. Heat-capacity measurements under uniaxial pressure using a piezo-driven device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:103903. [PMID: 33138600 DOI: 10.1063/5.0021919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
We report the development of a technique to measure heat capacity at large uniaxial pressure using a piezoelectric-driven device generating compressive and tensile strain in the sample. Our setup is optimized for temperatures ranging from 8 K down to millikelvin. Using an AC heat-capacity technique, we are able to achieve an extremely high resolution and to probe a homogeneously strained part of the sample. We demonstrate the capabilities of our setup on the unconventional superconductor Sr2RuO4. By replacing thermometer and adjusting the remaining setup accordingly, the temperature regime of the experiment can be adapted to other temperature ranges of interest.
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Affiliation(s)
- Y-S Li
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| | - R Borth
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| | - C W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| | - M Nicklas
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
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37
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Park J, Bartlett JM, Noad HML, Stern AL, Barber ME, König M, Hosoi S, Shibauchi T, Mackenzie AP, Steppke A, Hicks CW. Rigid platform for applying large tunable strains to mechanically delicate samples. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:083902. [PMID: 32872945 DOI: 10.1063/5.0008829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Response to uniaxial stress has become a major probe of electronic materials. Tunable uniaxial stress may be applied using piezoelectric actuators, and so far two methods have been developed to couple samples to actuators. In one, actuators apply force along the length of a free, beam-like sample, allowing very large strains to be achieved. In the other, samples are affixed directly to piezoelectric actuators, allowing the study of mechanically delicate materials. Here, we describe an approach that merges the two: thin samples are affixed to a substrate, which is then pressurized uniaxially using piezoelectric actuators. Using this approach, we demonstrate the application of large elastic strains to mechanically delicate samples: the van der Waals-bonded material FeSe and a sample of CeAuSb2 that was shaped with a focused ion beam.
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Affiliation(s)
- Joonbum Park
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Jack M Bartlett
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Hilary M L Noad
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Alexander L Stern
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Mark E Barber
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Markus König
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Suguru Hosoi
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Takasada Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Alexander Steppke
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
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38
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Abstract
We have measured the angle-resolved transverse resistivity (ARTR), a sensitive indicator of electronic anisotropy, in high-quality thin films of the unconventional superconductor Sr2RuO4 grown on various substrates. The ARTR signal, heralding the electronic nematicity or a large nematic susceptibility, is present and substantial already at room temperature and grows by an order of magnitude upon cooling down to 4 K. In Sr2RuO4 films deposited on tetragonal substrates the highest-conductivity direction does not coincide with any crystallographic axis. In films deposited on orthorhombic substrates it tends to align with the shorter axis; however, the magnitude of the anisotropy stays the same despite the large lattice distortion. These are strong indications of actual or incipient electronic nematicity in Sr2RuO4.
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39
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Nobukane H, Yanagihara K, Kunisada Y, Ogasawara Y, Isono K, Nomura K, Tanahashi K, Nomura T, Akiyama T, Tanda S. Co-appearance of superconductivity and ferromagnetism in a Ca 2RuO 4 nanofilm crystal. Sci Rep 2020; 10:3462. [PMID: 32103095 PMCID: PMC7044234 DOI: 10.1038/s41598-020-60313-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/10/2020] [Indexed: 12/03/2022] Open
Abstract
By tuning the physical and chemical pressures of layered perovskite materials we can realize the quantum states of both superconductors and insulators. By reducing the thickness of a layered crystal to a nanometer level, a nanofilm crystal can provide novel quantum states that have not previously been found in bulk crystals. Here we report the realization of high-temperature superconductivity in Ca2RuO4 nanofilm single crystals. Ca2RuO4 thin film with the highest transition temperature Tc (midpoint) of 64 K exhibits zero resistance in electric transport measurements. The superconducting critical current exhibited a logarithmic dependence on temperature and was enhanced by an external magnetic field. Magnetic measurements revealed a ferromagnetic transition at 180 K and diamagnetic magnetization due to superconductivity. Our results suggest the co-appearance of superconductivity and ferromagnetism in Ca2RuO4 nanofilm crystals. We also found that the induced bias current and the tuned film thickness caused a superconductor-insulator transition. The fabrication of micro-nanocrystals made of layered material enables us to discuss rich superconducting phenomena in ruthenates.
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Affiliation(s)
- Hiroyoshi Nobukane
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan. .,Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo, 060-8628, Japan.
| | - Kosei Yanagihara
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - Yuji Kunisada
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, 060-0828, Japan
| | - Yunito Ogasawara
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kakeru Isono
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kazushige Nomura
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - Keita Tanahashi
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, 060-0828, Japan
| | - Takahiro Nomura
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, 060-0828, Japan
| | - Tomohiro Akiyama
- Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo, 060-8628, Japan.,Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, 060-0828, Japan
| | - Satoshi Tanda
- Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo, 060-8628, Japan.,Department of Applied Physics, Hokkaido University, Sapporo, 060-8628, Japan
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40
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Momentum-resolved superconducting energy gaps of Sr 2RuO 4 from quasiparticle interference imaging. Proc Natl Acad Sci U S A 2020; 117:5222-5227. [PMID: 32094178 DOI: 10.1073/pnas.1916463117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sr2RuO4 has long been the focus of intense research interest because of conjectures that it is a correlated topological superconductor. It is the momentum space (k-space) structure of the superconducting energy gap [Formula: see text] on each band i that encodes its unknown superconducting order parameter. However, because the energy scales are so low, it has never been possible to directly measure the [Formula: see text] of Sr2RuO4 Here, we implement Bogoliubov quasiparticle interference (BQPI) imaging, a technique capable of high-precision measurement of multiband [Formula: see text] At T = 90 mK, we visualize a set of Bogoliubov scattering interference wavevectors [Formula: see text] consistent with eight gap nodes/minima that are all closely aligned to the [Formula: see text] crystal lattice directions on both the α and β bands. Taking these observations in combination with other very recent advances in directional thermal conductivity [E. Hassinger et al., Phys. Rev. X 7, 011032 (2017)], temperature-dependent Knight shift [A. Pustogow et al., Nature 574, 72-75 (2019)], time-reversal symmetry conservation [S. Kashiwaya et al., Phys. Rev B, 100, 094530 (2019)], and theory [A. T. Rømer et al., Phys. Rev. Lett. 123, 247001 (2019); H. S. Roising, T. Scaffidi, F. Flicker, G. F. Lange, S. H. Simon, Phys. Rev. Res. 1, 033108 (2019); and O. Gingras, R. Nourafkan, A. S. Tremblay, M. Côté, Phys. Rev. Lett. 123, 217005 (2019)], the BQPI signature of Sr2RuO4 appears most consistent with [Formula: see text] having [Formula: see text] [Formula: see text] symmetry.
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41
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Jin F, Gu M, Ma C, Guo EJ, Zhu J, Qu L, Zhang Z, Zhang K, Xu L, Chen B, Chen F, Gao G, Rondinelli JM, Wu W. Uniaxial Strain-Controlled Ground States in Manganite Films. NANO LETTERS 2020; 20:1131-1140. [PMID: 31978309 DOI: 10.1021/acs.nanolett.9b04506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Strongly correlated perovskite oxides exhibit a plethera of intriguing phenomena and stimulate a great potential for multifunctional device applications. Utilizing tunable uniaxial strain, rather than biaxial or anisotropic strain, delivered from the crystallography of a single crystal substrate to modify the ground state of strongly correlated perovskite oxides has rarely been addressed for phase-space control. Here, we show that the physical properties of La2/3Ca1/3MnO3 (LCMO) films are remarkably different depending on the crystallographic orientations of the orthorhombic NdGaO3 (NGO) substrates. More importantly, the antiferromagnetic charge-ordered insulating (COI) phase induced in the (100) or (001)-oriented LCMO films can be dramatically promoted (or suppressed) by a uniaxial tensile (or compressive) bending stress along the in-plane [010] direction. By contrast, the COI phase is nearly unaffected along the other transverse in-plane directions. Results from scanning transmission electron microscopy reveal that the (100)- or (001)-oriented LCMO films are uniaxially tensile strained along the [010] direction, while the LCMO/NGO(010) and LCMO/NGO(110) films remaining as a bulklike ferromagnetic metallic state exhibit a different strain state. Density functional theory calculations further reveal that the cooperatively increased Jahn-Teller distortion and charge ordering may be indispensible for the inducing and promoting of the COI phase. These findings provide a path to understand the correlation between local and extended structural distortions imparted by coherent epitaxy and the electronic states for quantum phase engineering.
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Affiliation(s)
- Feng Jin
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Mingqiang Gu
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Chao Ma
- College of Materials Science and Engineering , Hunan University , Changsha 410082 , China
| | - Er-Jia Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
- Center of Materials Science and Optoelectronics Engineering , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Jin Zhu
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Lili Qu
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Zixun Zhang
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Kexuan Zhang
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Liqiang Xu
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Binbin Chen
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Feng Chen
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Guanyin Gao
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - James M Rondinelli
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Wenbin Wu
- Anhui Key Laboratory of Condensed Matter at Extreme Conditions, High Magnetic Field Laboratory, and Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
- Institutes of Physical Science and Information Technology , Anhui University , Hefei 230601 , China
- Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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42
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Abstract
The bilayer perovskite Sr3Ru2O7 has been widely studied as a canonical strange metal. It exhibits T-linear resistivity and a T log(1/T) electronic specific heat in a field-tuned quantum critical fan. Criticality is known to occur in "hot" Fermi pockets with a high density of states close to the Fermi energy. We show that while these hot pockets occupy a small fraction of the Brillouin zone, they are responsible for the anomalous transport and thermodynamics of the material. Specifically, a scattering process in which two electrons from the large, "cold" Fermi surfaces scatter into one hot and one cold electron renders the ostensibly noncritical cold fermions a marginal Fermi liquid. From this fact the transport and thermodynamic phase diagram is reproduced in detail. Finally, we show that the same scattering mechanism into hot electrons that are instead localized near a 2D van Hove singularity explains the anomalous transport observed in strained Sr2RuO4.
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Affiliation(s)
| | - Erez Berg
- Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Sean A Hartnoll
- Department of Physics, Stanford University, Stanford, CA 94305
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
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43
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Gingras O, Nourafkan R, Tremblay AMS, Côté M. Superconducting Symmetries of Sr_{2}RuO_{4} from First-Principles Electronic Structure. PHYSICAL REVIEW LETTERS 2019; 123:217005. [PMID: 31809152 DOI: 10.1103/physrevlett.123.217005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Indexed: 06/10/2023]
Abstract
Although correlated electronic-structure calculations explain very well the normal state of Sr_{2}RuO_{4}, its superconducting symmetry is still unknown. Here we construct the spin and charge fluctuation pairing interactions based on its correlated normal state. Correlations significantly reduce ferromagnetic in favor of antiferromagnetic fluctuations and increase interorbital pairing. From the normal-state Eliashberg equations, we find spin-singlet d-wave pairing close to magnetic instabilities. Away from these instabilities, where charge fluctuations increase, we find two time-reversal symmetry-breaking spin triplets: an odd-frequency s wave, and a doubly degenerate interorbital pairing between d_{xy} and (d_{yz},d_{xz}).
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Affiliation(s)
- O Gingras
- Département de Physique and Regroupement Québécois sur les Matériaux de Pointe, Université de Montréal, C. P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - R Nourafkan
- Département de Physique, Institut quantique, Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - A-M S Tremblay
- Département de Physique, Institut quantique, Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - M Côté
- Département de Physique and Regroupement Québécois sur les Matériaux de Pointe, Université de Montréal, C. P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada
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44
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Fang YW, Yang R, Chen H. The complex non-collinear magnetic orderings in Ba 2YOsO 6: a new approach to tuning spin-lattice interactions and controlling magnetic orderings in frustrated complex oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:445803. [PMID: 31300630 DOI: 10.1088/1361-648x/ab31e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Frustrated magnets are one class of fascinating materials that host many intriguing phases such as spin ice, spin liquid and complex long-range magnetic orderings at low temperatures. In this work we use first-principles calculations to find that in a wide range of magnetically frustrated oxides, at zero temperature a number of non-collinear magnetic orderings are more stable than the type-I collinear ordering that is observed at finite temperatures. The emergence of non-collinear orderings in those complex oxides is due to higher-order exchange interactions that originate from second-row and third-row transition metal elements. This implies a collinear-to-noncollinear spin transition at sufficiently low temperatures in those frustrated complex oxides. Furthermore, we find that in a particular oxide Ba2YOsO6, experimentally feasible uniaxial strain can tune the material between two different non-collinear magnetic orderings. Our work predicts new non-collinear magnetic orderings in frustrated complex oxides at very low temperatures and provides a mechanical route to tuning complex non-collinear magnetic orderings in those materials.
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Affiliation(s)
- Yue-Wen Fang
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan. NYU-ECNU Institute of Physics, New York University, Shanghai, People's Republic of China
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45
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Anomalous anisotropic behaviour of spin-triplet proximity effect in Au/SrRuO 3/Sr 2RuO 4 junctions. Sci Rep 2019; 9:15827. [PMID: 31676832 PMCID: PMC6825120 DOI: 10.1038/s41598-019-52003-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/10/2019] [Indexed: 11/23/2022] Open
Abstract
Spin-polarized supercurrents can be generated with magnetic inhomogeneity at a ferromagnet/spin-singlet-superconductor interface. In such systems, complex magnetic inhomogeneity makes it difficult to functionalise the spin-polarized supercurrents. However, spin-polarized supercurrents in ferromagnet/spin-triplet-superconductor junctions can be controlled by the angle between magnetization and spin of Copper pairs (d-vector), that can effectively be utilized in developing of a field of research known as superconducting spintronics. Recently, we found induction of spin-triplet correlation into a ferromagnet SrRuO3 epitaxially deposited on a spin-triplet superconductor Sr2RuO4, without any electronic spin-flip scattering. Here, we present systematic magnetic field dependence of the proximity effect in Au/SrRuO3/Sr2RuO4 junctions. It is found that induced triplet correlations exhibit strongly anisotropic field response. Such behaviour is attributed to the rotation of the d-vector of Sr2RuO4. This anisotropic behaviour is in contrast with the vortex dynamic. Our results will stimulate study of interaction between ferromagnetism and unconventional superconductivity.
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46
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Pustogow A, Luo Y, Chronister A, Su YS, Sokolov DA, Jerzembeck F, Mackenzie AP, Hicks CW, Kikugawa N, Raghu S, Bauer ED, Brown SE. Constraints on the superconducting order parameter in Sr 2RuO 4 from oxygen-17 nuclear magnetic resonance. Nature 2019; 574:72-75. [PMID: 31548658 DOI: 10.1038/s41586-019-1596-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/15/2019] [Indexed: 11/09/2022]
Abstract
Phases of matter are usually identified through spontaneous symmetry breaking, especially regarding unconventional superconductivity and the interactions from which it originates. In that context, the superconducting state of the quasi-two-dimensional and strongly correlated perovskite Sr2RuO4 is considered to be the only solid-state analogue to the superfluid 3He-A phase1,2, with an odd-parity order parameter that is unidirectional in spin space for all electron momenta and breaks time-reversal symmetry. This characterization was recently called into question by a search for an expected 'split' transition in a Sr2RuO4 crystal under in-plane uniaxial pressure, which failed to find any such evidence; instead, a dramatic rise and a peak in a single-transition temperature were observed3,4. Here we use nuclear magnetic resonance (NMR) spectroscopy of oxygen-17, which is directly sensitive to the order parameter via hyperfine coupling to the electronic spin degrees of freedom, to probe the nature of superconductivity in Sr2RuO4 and its evolution under strain. A reduction of the Knight shift is observed for all strain values and at temperatures below the critical temperature, consistent with a drop in spin polarization in the superconducting state. In unstrained samples, our results contradict a body of previous NMR work reporting no change in the Knight shift5 and the most prevalent theoretical interpretation of the order parameter as a chiral p-wave state. Sr2RuO4 is an extremely clean layered perovskite and its superconductivity emerges from a strongly correlated Fermi liquid, and our work imposes tight constraints on the order parameter symmetry of this archetypal system.
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Affiliation(s)
- A Pustogow
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA.
| | - Yongkang Luo
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA. .,Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China.
| | - A Chronister
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Y-S Su
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - D A Sokolov
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - F Jerzembeck
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.,School of Physics and Astronomy, University of St Andrews, St Andrews, UK
| | - C W Hicks
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - N Kikugawa
- National Institute for Materials Science, Tsukuba, Japan
| | - S Raghu
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - S E Brown
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA.
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47
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Universal superconducting precursor in three classes of unconventional superconductors. Nat Commun 2019; 10:2729. [PMID: 31227719 PMCID: PMC6588566 DOI: 10.1038/s41467-019-10635-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 05/20/2019] [Indexed: 11/09/2022] Open
Abstract
A pivotal challenge posed by unconventional superconductors is to unravel how superconductivity emerges upon cooling from the generally complex normal state. Here, we use nonlinear magnetic response, a probe that is uniquely sensitive to the superconducting precursor, to uncover remarkable universal behaviour in three distinct classes of oxide superconductors: strontium titanate, strontium ruthenate, and the cuprate high-Tc materials. We find unusual exponential temperature dependence of the diamagnetic response above the transition temperature Tc, with a characteristic temperature scale that strongly varies with Tc. We correlate this scale with the sensitivity of Tc to local stress and show that it is influenced by intentionally-induced structural disorder. The universal behaviour is therefore caused by intrinsic, self-organized structural inhomogeneity, inherent to the oxides' perovskite-based structure. The prevalence of such inhomogeneity has far-reaching implications for the interpretation of electronic properties of perovskite-related oxides in general.
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48
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Kim HH, Souliou SM, Barber ME, Lefrançois E, Minola M, Tortora M, Heid R, Nandi N, Borzi RA, Garbarino G, Bosak A, Porras J, Loew T, König M, Moll PJW, Mackenzie AP, Keimer B, Hicks CW, Le Tacon M. Uniaxial pressure control of competing orders in a high-temperature superconductor. Science 2019; 362:1040-1044. [PMID: 30498124 DOI: 10.1126/science.aat4708] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 10/25/2018] [Indexed: 11/02/2022]
Abstract
Cuprates exhibit antiferromagnetic, charge density wave (CDW), and high-temperature superconducting ground states that can be tuned by means of doping and external magnetic fields. However, disorder generated by these tuning methods complicates the interpretation of such experiments. Here, we report a high-resolution inelastic x-ray scattering study of the high-temperature superconductor YBa2Cu3O6.67 under uniaxial stress, and we show that a three-dimensional long-range-ordered CDW state can be induced through pressure along the a axis, in the absence of magnetic fields. A pronounced softening of an optical phonon mode is associated with the CDW transition. The amplitude of the CDW is suppressed below the superconducting transition temperature, indicating competition with superconductivity. The results provide insights into the normal-state properties of cuprates and illustrate the potential of uniaxial-pressure control of competing orders in quantum materials.
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Affiliation(s)
- H-H Kim
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - S M Souliou
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - M E Barber
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - E Lefrançois
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany.,European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - M Minola
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - M Tortora
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - R Heid
- Institute for Solid State Physics, Karlsruhe Institute of Technology, Hermann-v.-Helmholtz-Platz 176344 Karlsruhe, Germany
| | - N Nandi
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - R A Borzi
- Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), UNLP-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), La Plata, Argentina and Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), c.c. 16, suc. 4, 1900 La Plata, Argentina
| | - G Garbarino
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - A Bosak
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - J Porras
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - T Loew
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - M König
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - P J W Moll
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany.,Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - B Keimer
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - C W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - M Le Tacon
- Institute for Solid State Physics, Karlsruhe Institute of Technology, Hermann-v.-Helmholtz-Platz 176344 Karlsruhe, Germany.
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49
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Barber ME, Steppke A, Mackenzie AP, Hicks CW. Piezoelectric-based uniaxial pressure cell with integrated force and displacement sensors. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:023904. [PMID: 30831706 DOI: 10.1063/1.5075485] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
We present a design for a piezoelectric-driven uniaxial stress cell suitable for use at ambient and cryogenic temperatures and that incorporates both a displacement and a force sensor. The cell has a diameter of 46 mm and a height of 13 mm. It can apply a zero-load displacement of up to ∼45 μm and a zero-displacement force of up to ∼245 N. With combined knowledge of the displacement and force applied to the sample, it can quickly be determined whether the sample and its mounts remain within their elastic limits. In tests on the oxide metal Sr2RuO4, we found that at room temperature serious plastic deformation of the sample onset at a uniaxial stress of ∼0.2 GPa, while at 5 K the sample deformation remained elastic up to almost 2 GPa. This result highlights the usefulness of in situ tuning, in which the force can be applied after cooling samples to cryogenic temperatures.
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Affiliation(s)
- Mark E Barber
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden 01187, Germany
| | - Alexander Steppke
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden 01187, Germany
| | - Andrew P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden 01187, Germany
| | - Clifford W Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden 01187, Germany
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50
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Abstract
High-quality single crystals are essentially needed for the investigation of the novel bulk properties of unconventional superconductors. The availability of such crystals grown by the floating-zone method has helped to unveil the unconventional superconductivity of the layered perovskite Sr2RuO4, which is considered as a strong candidate of a topological spin-triplet superconductor. Yet, recent progress of investigations urges further efforts to obtain ultimately high-quality crystalline samples. In this paper, we focus on the method of preparation of feed rods for the floating-zone melting and report on the improvements of the crystal growth. We present details of the improved methods used to obtain crystals with superconducting transition temperatures Tc that are consistently as high as 1.4 K, as well as the properties of these crystals.
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