1
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Sim S, Jeong MY, Lee H, Lee DHD, Han MJ. Chemical effect on the Van Hove singularity in superconducting kagome metal AV 3Sb 5 (A = K, Rb, and Cs). Phys Chem Chem Phys 2024; 26:11715-11721. [PMID: 38563514 DOI: 10.1039/d4cp00517a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
To understand the alkali-metal-dependent material properties of recently discovered AV3Sb5 (A = K, Rb, and Cs), we conducted a detailed electronic structure analysis based on first-principles density functional theory calculations. Contrary to the case of A = K and Rb, the energetic positions of the low-lying Van Hove singularities are reversed in CsV3Sb5, and the characteristic higher-order Van Hove point gets closer to the Fermi level. We found that this notable difference can be attributed to the chemical effect, apart from structural differences. Due to their different orbital compositions, Van Hove points show qualitatively different responses to the structure changes. A previously unnoticed highest lying point can be lowered, locating close to or even below the other ones in response to a reasonable range of bi- and uni-axial strain. Our results can be useful in better understanding the material-dependent features reported in this family and in realizing experimental control of exotic quantum phases.
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Affiliation(s)
- Sangjun Sim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
| | - Min Yong Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
| | - Hyunggeun Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
| | - Dong Hyun David Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
| | - Myung Joon Han
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
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2
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Wei L, Xu Q, He Y, Li Q, Huang Y, Zhu W, Watanabe K, Taniguchi T, Claassen M, Rhodes DA, Kennes DM, Xian L, Rubio A, Wang L. Linear resistivity at van Hove singularities in twisted bilayer WSe 2. Proc Natl Acad Sci U S A 2024; 121:e2321665121. [PMID: 38593078 PMCID: PMC11032435 DOI: 10.1073/pnas.2321665121] [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: 12/10/2023] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
Different mechanisms driving a linear temperature dependence of the resistivity ρ ∼ T at van Hove singularities (VHSs) or metal-insulator transitions when doping a Mott insulator are being debated intensively with competing theoretical proposals. We experimentally investigate this using the exceptional tunability of twisted bilayer (TB) WSe2 by tracking the parameter regions where linear-in-T resistivity is found in dependency of displacement fields, filling, and magnetic fields. We find that even when the VHSs are tuned rather far away from the half-filling point and the Mott insulating transition is absent, the T-linear resistivity persists at the VHSs. When doping away from the VHSs, the T-linear behavior quickly transitions into a Fermi liquid behavior with a T2 relation. No apparent dependency of the linear-in-T resistivity, besides a rather strong change of prefactor, is found when applying displacement fields as long as the filling is tuned to the VHSs, including D ∼ 0.28 V/nm where a high-order VHS is expected. Intriguingly, such non-Fermi liquid linear-in-T resistivity persists even when magnetic fields break the spin-degeneracy of the VHSs at which point two linear in T regions emerge, for each of the split VHSs separately. This points to a mechanism of enhanced scattering at generic VHSs rather than only at high-order VHSs or by a quantum critical point during a Mott transition. Our findings provide insights into the many-body consequences arising out of VHSs, especially the non-Fermi liquid behavior found in moiré materials.
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Affiliation(s)
- LingNan Wei
- National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing210093, China
| | - Qiaoling Xu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, China
- College of Physics and Electronic Engineering, Center for Computational Sciences, Sichuan Normal University, Chengdu610068, China
| | - Yangchen He
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI53706
| | - Qingxin Li
- National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing210093, China
| | - Yan Huang
- National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing210093, China
| | - Wang Zhu
- National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing210093, China
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, Tsukuba305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba305-0044, Japan
| | - Martin Claassen
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA19104
| | - Daniel A. Rhodes
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI53706
| | - Dante M. Kennes
- Institut für Theorie der Statistischen Physik, Rheinisch-Westfälische Technische Hochschule Aachen University and Jülich Aachen Research Alliance-Fundamentals of Future Information Technology, Aachen52056, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg22761, Germany
| | - Lede Xian
- Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, China
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg22761, Germany
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg22761, Germany
- Center for Computational Quantum Physics, Simons Foundation Flatiron Institute, New York, NY10010
| | - Lei Wang
- National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing210093, China
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3
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Han X, Zhan J, Zhang FC, Hu J, Wu X. Robust topological superconductivity in spin-orbit coupled systems at higher-order van Hove filling. Sci Bull (Beijing) 2024; 69:319-324. [PMID: 38105164 DOI: 10.1016/j.scib.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 10/19/2023] [Accepted: 11/22/2023] [Indexed: 12/19/2023]
Abstract
Van Hove singularities in proximity to the Fermi level promote electronic interactions and generate diverse competing instabilities. It is also known that a nontrivial Berry phase derived from spin-orbit coupling can introduce an intriguing decoration into the interactions and thus alter correlated phenomena. However, it is unclear how and what type of new physics can emerge in a system featured by the interplay between van Hove singularities (VHSs) and the Berry phase. Here, based on a general Rashba model on the square lattice, we comprehensively explore such an interplay and its significant influence on the competing electronic instabilities by performing a parquet renormalization group analysis. Despite the existence of a variety of comparable fluctuations in the particle-particle and particle-hole channels associated with higher-order VHSs, we find that the chiral p±ip pairings emerge as two stable fixed trajectories within the generic interaction parameter space, namely the system becomes a robust topological superconductor. The chiral pairings stem from the hopping interaction induced by the nontrivial Berry phase. The possible experimental realization and implications are discussed. Our work sheds new light on the correlated states in quantum materials with strong spin-orbit coupling (SOC) and offers fresh insights into the exploration of topological superconductivity.
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Affiliation(s)
- Xinloong Han
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
| | - Jun Zhan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Fu-Chun Zhang
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jiangping Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
| | - Xianxin Wu
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
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4
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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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5
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Marques CA, Rhodes LC, Benedičič I, Naritsuka M, Naden AB, Li Z, Komarek AC, Mackenzie AP, Wahl P. Atomic-scale imaging of emergent order at a magnetic field-induced Lifshitz transition. SCIENCE ADVANCES 2022; 8:eabo7757. [PMID: 36179031 PMCID: PMC9524824 DOI: 10.1126/sciadv.abo7757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
The phenomenology and radical changes seen in material properties traversing a quantum phase transition have captivated condensed matter research over the past decades. Strong electronic correlations lead to exotic electronic ground states, including magnetic order, nematicity, and unconventional superconductivity. Providing a microscopic model for these requires detailed knowledge of the electronic structure in the vicinity of the Fermi energy, promising a complete understanding of the physics of the quantum critical point. Here, we demonstrate such a measurement at the surface of Sr3Ru2O7. Our results show that, even in zero field, the electronic structure is strongly C2 symmetric and that a magnetic field drives a Lifshitz transition and induces a charge-stripe order. We track the changes of the electronic structure as a function of field via quasiparticle interference imaging at ultralow temperatures. Our results provide a complete microscopic picture of the field-induced changes of the electronic structure across the Lifshitz transition.
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Affiliation(s)
- Carolina A. Marques
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
| | - Luke C. Rhodes
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
| | - Izidor Benedičič
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
| | - Masahiro Naritsuka
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
| | - Aaron B. Naden
- School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Zhiwei Li
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Alexander C. Komarek
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Andrew P. Mackenzie
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Peter Wahl
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
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6
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Lester C, Ramos S, Perry RS, Croft TP, Laver M, Bewley RI, Guidi T, Hiess A, Wildes A, Forgan EM, Hayden SM. Magnetic-field-controlled spin fluctuations and quantum critically in Sr 3Ru 2O 7. Nat Commun 2021; 12:5798. [PMID: 34608160 PMCID: PMC8490391 DOI: 10.1038/s41467-021-26068-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/14/2021] [Indexed: 11/24/2022] Open
Abstract
When the transition temperature of a continuous phase transition is tuned to absolute zero, new ordered phases and physical behaviour emerge in the vicinity of the resulting quantum critical point. Sr3Ru2O7 can be tuned through quantum criticality with magnetic field at low temperature. Near its critical field Bc it displays the hallmark T-linear resistivity and a \documentclass[12pt]{minimal}
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\begin{document}$$T\,{{{{{{\mathrm{log}}}}}}}\,(1/T)$$\end{document}Tlog(1/T) electronic heat capacity behaviour of strange metals. However, these behaviours have not been related to any critical fluctuations. Here we use inelastic neutron scattering to reveal the presence of collective spin fluctuations whose relaxation time and strength show a nearly singular variation with magnetic field as Bc is approached. The large increase in the electronic heat capacity and entropy near Bc can be understood quantitatively in terms of the scattering of conduction electrons by these spin-fluctuations. On entering the spin-density-wave ordered phase present near Bc, the fluctuations become stronger suggesting that the order is stabilised through an “order-by-disorder” mechanism. Sr3Ru2O7 exhibits a quantum critical point tunable by magnetic field and has been widely used in the study of criticality. Here, by using inelastic neutron scattering, the authors measure collective magnetic excitations near the quantum critical point and relate them to thermodynamic properties and spin density wave order.
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Affiliation(s)
- C Lester
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK
| | - S Ramos
- School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, UK
| | - R S Perry
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - T P Croft
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK
| | - M Laver
- School of Physics and Astronomy, University of Birmingham, Birmingham, BT15 2TT, UK
| | - R I Bewley
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - T Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - A Hiess
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble, France.,European Spallation Source ERIC, P.O. Box 176, 22100, Lund, Sweden
| | - A Wildes
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble, France
| | - E M Forgan
- School of Physics and Astronomy, University of Birmingham, Birmingham, BT15 2TT, UK
| | - S M Hayden
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK.
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7
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Marques CA, Rhodes LC, Fittipaldi R, Granata V, Yim CM, Buzio R, Gerbi A, Vecchione A, Rost AW, Wahl P. Magnetic-Field Tunable Intertwined Checkerboard Charge Order and Nematicity in the Surface Layer of Sr 2 RuO 4. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100593. [PMID: 34176160 DOI: 10.1002/adma.202100593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/21/2021] [Indexed: 06/13/2023]
Abstract
In strongly correlated electron materials, the electronic, spin, and charge degrees of freedom are closely intertwined. This often leads to the stabilization of emergent orders that are highly sensitive to external physical stimuli promising opportunities for technological applications. In perovskite ruthenates, this sensitivity manifests in dramatic changes of the physical properties with subtle structural details of the RuO6 octahedra, stabilizing enigmatic correlated ground states, from a hotly debated superconducting state via electronic nematicity and metamagnetic quantum criticality to ferromagnetism. Here, it is demonstrated that the rotation of the RuO6 octahedra in the surface layer of Sr2 RuO4 generates new emergent orders not observed in the bulk material. Through atomic-scale spectroscopic characterization of the low-energy electronic states, four van Hove singularities are identified in the vicinity of the Fermi energy. The singularities can be directly linked to intertwined nematic and checkerboard charge order. Tuning of one of these van Hove singularities by magnetic field is demonstrated, suggesting that the surface layer undergoes a Lifshitz transition at a magnetic field of ≈32T. The results establish the surface layer of Sr2 RuO4 as an exciting 2D correlated electron system and highlight the opportunities for engineering the low-energy electronic states in these systems.
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Affiliation(s)
- Carolina A Marques
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, UK
| | - Luke C Rhodes
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, UK
| | - Rosalba Fittipaldi
- CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, Fisciano, I-84084, Italy
| | - Veronica Granata
- Dipartimento di Fisica "E. R. Caianiello" Universitá di Salerno, Fisciano, Salerno, I-84084, Italy
| | - Chi Ming Yim
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, UK
| | - Renato Buzio
- CNR-SPIN, Corso F.M. Perrone 24, Genova, 16152, Italy
| | - Andrea Gerbi
- CNR-SPIN, Corso F.M. Perrone 24, Genova, 16152, Italy
| | - Antonio Vecchione
- CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, Fisciano, I-84084, Italy
| | - Andreas W Rost
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, UK
- Max-Planck-Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Peter Wahl
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, UK
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8
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Phong TC, Lam VT, Hoi BD. Tuning electronic phase in noncentrosymmetric quantum spin Hall insulators through physical stimuli. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:325502. [PMID: 34044386 DOI: 10.1088/1361-648x/ac05e4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
In this work, the perturbation-induced phase transitions in noncentrosymmetric quantum spin Hall insulators (QSHIs) are analytically addressed. In particular, the dilute charged impurity, the electric field, and the Zeeman splitting field are considered within the tight-binding Hamiltonian model, Green's function approach, and the Born approximation. Following theC3vsymmetry breaking in the PbBiI compound as a representative QSHI, the band gap becomes larger via the electric field, while the system transits to the semimetallic phase via the dilute charged impurities and Zeeman field, modifying the degenerate states in the electronic density of states. While the coexistence of electric field and impurities demonstrate that the system backs to its initial semiconducting phase, the combined Zeeman field and impurities do not alter the robust semimetallic phase.
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Affiliation(s)
- Tran C Phong
- Center for Theoretical and Computational Physics, University of Education, Hue University, Hue 530000, Viet Nam
| | - Vo T Lam
- Faculty of Natural Sciences Pedagogy, Sai Gon University, 273 An Duong Vuong Str., District 5, Ho Chi Minh City, Vietnam
| | - Bui D Hoi
- Center for Theoretical and Computational Physics, University of Education, Hue University, Hue 530000, Viet Nam
- Department of Physics, University of Education, Hue University, Hue 530000, Vietnam
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9
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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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10
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Wang J, Santos LH. Classification of Topological Phase Transitions and van Hove Singularity Steering Mechanism in Graphene Superlattices. PHYSICAL REVIEW LETTERS 2020; 125:236805. [PMID: 33337183 DOI: 10.1103/physrevlett.125.236805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/21/2020] [Indexed: 06/12/2023]
Abstract
We study quantum phase transitions in graphene superlattices in external magnetic fields, where a framework is presented to classify multiflavor Dirac fermion critical points describing hopping-tuned topological phase transitions of integer and fractional Hofstadter-Chern insulators. We argue and provide numerical support for the existence of transitions that can be explained by a nontrivial interplay of Chern bands and van Hove singularities near charge neutrality. This work provides a route to critical phenomena beyond conventional quantum Hall plateau transitions.
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Affiliation(s)
- Jian Wang
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Luiz H Santos
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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11
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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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12
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Yuan NFQ, Isobe H, Fu L. Magic of high-order van Hove singularity. Nat Commun 2019; 10:5769. [PMID: 31852901 PMCID: PMC6920381 DOI: 10.1038/s41467-019-13670-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/14/2019] [Indexed: 11/29/2022] Open
Abstract
The van Hove singularity in density of states generally exists in periodic systems due to the presence of saddle points of energy dispersion in momentum space. We introduce a new type of van Hove singularity in two dimensions, resulting from high-order saddle points and exhibiting power-law divergent density of states. We show that high-order van Hove singularity can be generally achieved by tuning the band structure with a single parameter in moiré superlattices, such as twisted bilayer graphene by tuning twist angle or applying pressure, and trilayer graphene by applying vertical electric field. Correlation effects from high-order van Hove singularity near Fermi level are also discussed.
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Affiliation(s)
- Noah F Q Yuan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Hiroki Isobe
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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