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Topological Doping and Superconductivity in Cuprates: An Experimental Perspective. Symmetry (Basel) 2021. [DOI: 10.3390/sym13122365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Hole doping into a correlated antiferromagnet leads to topological stripe correlations, involving charge stripes that separate antiferromagnetic spin stripes of opposite phases. The topological spin stripe order causes the spin degrees of freedom within the charge stripes to feel a geometric frustration with their environment. In the case of cuprates, where the charge stripes have the character of a hole-doped two-leg spin ladder, with corresponding pairing correlations, anti-phase Josephson coupling across the spin stripes can lead to a pair-density-wave order in which the broken translation symmetry of the superconducting wave function is accommodated by pairs with finite momentum. This scenario is now experimentally verified by recently reported measurements on La2−xBaxCuO4 with x=1/8. While pair-density-wave order is not common as a cuprate ground state, it provides a basis for understanding the uniform d-wave order that is more typical in superconducting cuprates.
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Maity A, Dutta R, Paulus W. Stripe Discommensuration and Spin Dynamics of Half-Doped Pr_{3/2}Sr_{1/2}NiO_{4}. PHYSICAL REVIEW LETTERS 2020; 124:147202. [PMID: 32338981 DOI: 10.1103/physrevlett.124.147202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 02/15/2020] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
We present inelastic neutron scattering measurements of magnetic excitations in stripe ordered Pr_{3/2}Sr_{1/2}NiO_{4} at T∼10 K. For the observed magnetic incommensurability ε=0.4, we have incorporated a stripe discommensuration model in our linear spin wave calculation and obtained best agreement with the measured spin wave dispersion, especially to explain the symmetrical outward shift of the magnetic peaks from Néel ordered zone center in energy range 35 to 45 meV. Our study indicates the prerequisite to consider a discommensurated spin stripe unit with proper out-of-plane and in-plane exchange interactions in between Ni^{2+} spins to describe the observed spin wave characteristics in Pr_{3/2}Sr_{1/2}NiO_{4}.
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Affiliation(s)
- Avishek Maity
- Institut für Physikalische Chemie, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85747 Garching, Germany
| | - Rajesh Dutta
- Institut für Kristallographie, RWTH Aachen Universität, 52066 Aachen, Germany
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany
| | - Werner Paulus
- Institut Charles Gerhardt Montpellier, Université de Montpellier, 34095 Montpellier, France
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Freeman PG, Giblin SR, Skoulatos M, Mole RA, Prabhakaran D. Wave Vector Difference of Magnetic Bragg Reflections and Low Energy Magnetic Excitations in Charge-stripe Ordered La2NiO4.11. Sci Rep 2019; 9:14468. [PMID: 31594985 PMCID: PMC6783545 DOI: 10.1038/s41598-019-50904-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/10/2019] [Indexed: 11/09/2022] Open
Abstract
We report on the magnetism of charge-stripe ordered La2NiO4.11±0.01 by neutron scattering and μSR. On going towards zero energy transfer there is an observed wave vector offset in the centring of the magnetic excitations and magnetic Bragg reflections, meaning the excitations cannot be described as Goldstone modes of the magnetic order. Weak transverse field μSR measurements determine the magnetically order volume fraction is 87% from the two stripe twins, and the temperature evolution of the magnetic excitations is consistent with the low energy excitations coming from the magnetically ordered volume of the material. We will discuss how these results contrast with the proposed origin of a similar wave vector offset recently observed in a La-based cuprate, and possible origins of this effect in La2NiO4.11.
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Coslovich G, Kemper AF, Behl S, Huber B, Bechtel HA, Sasagawa T, Martin MC, Lanzara A, Kaindl RA. Ultrafast dynamics of vibrational symmetry breaking in a charge-ordered nickelate. SCIENCE ADVANCES 2017; 3:e1600735. [PMID: 29202025 PMCID: PMC5706742 DOI: 10.1126/sciadv.1600735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
The ability to probe symmetry-breaking transitions on their natural time scales is one of the key challenges in nonequilibrium physics. Stripe ordering represents an intriguing type of broken symmetry, where complex interactions result in atomic-scale lines of charge and spin density. Although phonon anomalies and periodic distortions attest the importance of electron-phonon coupling in the formation of stripe phases, a direct time-domain view of vibrational symmetry breaking is lacking. We report experiments that track the transient multi-terahertz response of the model stripe compound La1.75Sr0.25NiO4, yielding novel insight into its electronic and structural dynamics following an ultrafast optical quench. We find that although electronic carriers are immediately delocalized, the crystal symmetry remains initially frozen-as witnessed by time-delayed suppression of zone-folded Ni-O bending modes acting as a fingerprint of lattice symmetry. Longitudinal and transverse vibrations react with different speeds, indicating a strong directionality and an important role of polar interactions. The hidden complexity of electronic and structural coupling during stripe melting and formation, captured here within a single terahertz spectrum, opens new paths to understanding symmetry-breaking dynamics in solids.
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Affiliation(s)
- Giacomo Coslovich
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Alexander F. Kemper
- Computational Research Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Sascha Behl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Bernhard Huber
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Hans A. Bechtel
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Takao Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - Michael C. Martin
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Robert A. Kaindl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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Fabbris G, Meyers D, Xu L, Katukuri VM, Hozoi L, Liu X, Chen ZY, Okamoto J, Schmitt T, Uldry A, Delley B, Gu GD, Prabhakaran D, Boothroyd AT, van den Brink J, Huang DJ, Dean MPM. Doping Dependence of Collective Spin and Orbital Excitations in the Spin-1 Quantum Antiferromagnet La_{2-x}Sr_{x}NiO_{4} Observed by X Rays. PHYSICAL REVIEW LETTERS 2017; 118:156402. [PMID: 28452512 DOI: 10.1103/physrevlett.118.156402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Indexed: 05/23/2023]
Abstract
We report the first empirical demonstration that resonant inelastic x-ray scattering (RIXS) is sensitive to collective magnetic excitations in S=1 systems by probing the Ni L_{3} edge of La_{2-x}Sr_{x}NiO_{4} (x=0, 0.33, 0.45). The magnetic excitation peak is asymmetric, indicating the presence of single and multi-spin-flip excitations. As the hole doping level is increased, the zone boundary magnon energy is suppressed at a much larger rate than that in hole doped cuprates. Based on the analysis of the orbital and charge excitations observed by RIXS, we argue that this difference is related to the orbital character of the doped holes in these two families. This work establishes RIXS as a probe of fundamental magnetic interactions in nickelates opening the way towards studies of heterostructures and ultrafast pump-probe experiments.
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Affiliation(s)
- G Fabbris
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - D Meyers
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - L Xu
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstraße, 20, 01069 Dresden, Germany
| | - V M Katukuri
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstraße, 20, 01069 Dresden, Germany
| | - L Hozoi
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstraße, 20, 01069 Dresden, Germany
| | - X Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Z-Y Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - J Okamoto
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - T Schmitt
- Research Department "Synchotron Radiation and Nanotechnology", Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Uldry
- Condensed Matter Theory Group, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - B Delley
- Condensed Matter Theory Group, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G D Gu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - D Prabhakaran
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford, OX1 3PU, United Kingdom
| | - A T Boothroyd
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford, OX1 3PU, United Kingdom
| | - J van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstraße, 20, 01069 Dresden, Germany
| | - D J Huang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - M P M Dean
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
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Direct observation of dynamic charge stripes in La2-xSrxNiO4. Nat Commun 2014; 5:3467. [PMID: 24632780 DOI: 10.1038/ncomms4467] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/18/2014] [Indexed: 11/08/2022] Open
Abstract
The insulator-to-metal transition continues to be a challenging subject, especially when electronic correlations are strong. In layered compounds, such as La2-xSrxNiO4 and La2-xBaxCuO4, the doped charge carriers can segregate into periodically spaced charge stripes separating narrow domains of antiferromagnetic order. Although there have been theoretical proposals of dynamically fluctuating stripes, direct spectroscopic evidence of charge-stripe fluctuations has been lacking. Here we report the detection of critical lattice fluctuations, driven by charge-stripe correlations, in La2-xSrxNiO4 using inelastic neutron scattering. This scattering is detected at large momentum transfers where the magnetic form factor suppresses the spin fluctuation signal. The lattice fluctuations associated with the dynamic charge stripes are narrow in q and broad in energy. They are strongest near the charge-stripe melting temperature. Our results open the way towards the quantitative theory of dynamic stripes and for directly detecting dynamical charge stripes in other strongly correlated systems, including high-temperature superconductors such as La2-xSrxCuO4.
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Seibold G, Lorenzana J. Magnetic fluctuations of stripes in the high temperature cuprate superconductors. PHYSICAL REVIEW LETTERS 2005; 94:107006. [PMID: 15783510 DOI: 10.1103/physrevlett.94.107006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Indexed: 05/24/2023]
Abstract
Within the time-dependent Gutzwiller approximation for the Hubbard model we compute the magnetic fluctuations of vertical metallic stripes with parameters appropriate for La(1.875)Ba(0.125)CuO(4) (LBCO). For bond- and site-centered stripes the excitation spectra are similar, consisting of a low-energy incommensurate acoustic branch which merges into a "resonance peak" at the antiferromagnetic wave vector and several high-energy optical branches. The acoustic branch is similar to the result of theories assuming localized spins whereas the optical branches are significantly different. Results are in good agreement with a recent inelastic neutron study of LBCO.
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Affiliation(s)
- G Seibold
- Institut für Physik, BTU Cottbus, Post Box 101344, 03013 Cottbus, Germany
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Hotta T, Dagotto E. Orbital ordering, new phases, and stripe formation in doped layered nickelates. PHYSICAL REVIEW LETTERS 2004; 92:227201. [PMID: 15245255 DOI: 10.1103/physrevlett.92.227201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Indexed: 05/24/2023]
Abstract
Ground-state properties of layered nickelates are investigated based on the orbital-degenerate Hubbard model coupled with lattice distortions, by using numerical techniques. The Néel state composed of spin S=1 ions is confirmed in the undoped limit x = 0. At x = 1/2, novel antiferromagnetic states, called CE- and E-type phases, are found by increasing the Hund's coupling. (3x2-r2/3y2-r2)-type orbital ordering is predicted to occur in a checkerboard-type charge-ordered state. At x = 1/3, both Coulombic and phononic interactions are found to be important, since the former stabilizes the spin stripe, while the latter leads to the striped charge order.
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Affiliation(s)
- Takashi Hotta
- Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195, Japan
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