1
|
Kauch A, Pudleiner P, Astleithner K, Thunström P, Ribic T, Held K. Generic Optical Excitations of Correlated Systems: π-tons. PHYSICAL REVIEW LETTERS 2020; 124:047401. [PMID: 32058776 DOI: 10.1103/physrevlett.124.047401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 10/12/2019] [Indexed: 06/10/2023]
Abstract
The interaction of light with solids gives rise to new bosonic quasiparticles, with the exciton being-undoubtedly-the most famous of these polaritons. While excitons are the generic polaritons of semiconductors, we show that for strongly correlated systems another polariton is prevalent-originating from the dominant antiferromagnetic or charge density wave fluctuations in these systems. As these are usually associated with a wave vector (π,π,…) or close to it, we propose to call the derived polaritons π-tons. These π-tons yield the leading vertex correction to the optical conductivity in all correlated models studied: the Hubbard, the extended Hubbard model, the Falicov-Kimball, and the Pariser-Parr-Pople model, both in the insulating and in the metallic phase.
Collapse
Affiliation(s)
- A Kauch
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - P Pudleiner
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
- Institute of Theoretical and Computational Physics, Graz University of Technology, 8010 Graz, Austria
| | - K Astleithner
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - P Thunström
- Department of Physics and Astronomy, Materials Theory, Uppsala University, 751 20 Uppsala, Sweden
| | - T Ribic
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - K Held
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| |
Collapse
|
2
|
Robinson NJ, Johnson PD, Rice TM, Tsvelik AM. Anomalies in the pseudogap phase of the cuprates: competing ground states and the role of umklapp scattering. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:126501. [PMID: 31300626 DOI: 10.1088/1361-6633/ab31ed] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Over the past two decades, advances in computational algorithms have revealed a curious property of the two-dimensional Hubbard model (and related theories) with hole doping: the presence of close-in-energy competing ground states that display very different physical properties. On the one hand, there is a complicated state exhibiting intertwined spin, charge, and pair density wave orders. We call this 'type A'. On the other hand, there is a uniform d-wave superconducting state that we denote as 'type B'. We advocate, with the support of both microscopic theoretical calculations and experimental data, dividing the high-temperature cuprate superconductors into two corresponding families, whose properties reflect either the type A or type B ground states at low temperatures. We review the anomalous properties of the pseudogap phase that led us to this picture, and present a modern perspective on the role that umklapp scattering plays in these phenomena in the type B materials. This reflects a consistent framework that has emerged over the last decade, in which Mott correlations at weak coupling drive the formation of the pseudogap. We discuss this development, recent theory and experiments, and open issues.
Collapse
Affiliation(s)
- Neil J Robinson
- Institute for Theoretical Physics, University of Amsterdam, Science Park 904, Postbus 94485, 1098 XH Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
3
|
Hepting M, Chaix L, Huang EW, Fumagalli R, Peng YY, Moritz B, Kummer K, Brookes NB, Lee WC, Hashimoto M, Sarkar T, He JF, Rotundu CR, Lee YS, Greene RL, Braicovich L, Ghiringhelli G, Shen ZX, Devereaux TP, Lee WS. Three-dimensional collective charge excitations in electron-doped copper oxide superconductors. Nature 2018; 563:374-378. [PMID: 30429543 DOI: 10.1038/s41586-018-0648-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/22/2018] [Indexed: 11/09/2022]
Abstract
High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12.
Collapse
Affiliation(s)
- M Hepting
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - L Chaix
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - E W Huang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - R Fumagalli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
| | - Y Y Peng
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,Department of Physics and Seitz Materials Research Lab, University of Illinois, Urbana, IL, USA
| | - B Moritz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - N B Brookes
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - W C Lee
- Department of Physics, Binghamton University, Binghamton, NY, USA
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - T Sarkar
- Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD, USA
| | - J-F He
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Department of Physics, University of Science and Technology of China, Hefei, China
| | - C R Rotundu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - Y S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - R L Greene
- Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD, USA
| | - L Braicovich
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - G Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,CNR-SPIN, Politecnico di Milano, Milan, Italy
| | - Z X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
| | - W S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
| |
Collapse
|
4
|
Ekino T, Gabovich AM, Suan Li M, Szymczak H, Voitenko AI. Quasiparticle conductance-voltage characteristics for break junctions involving d-wave superconductors: charge-density-wave effects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:505602. [PMID: 29105650 DOI: 10.1088/1361-648x/aa9867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Quasiparticle tunnel conductance-voltage characteristics (CVCs), [Formula: see text], were calculated for break junctions (BJs) made up of layered d-wave superconductors partially gapped by charge-density waves (CDWs). The current is assumed to flow in the ab-plane of electrodes. The influence of CDWs is analyzed by comparing the resulting CVCs with CVCs calculated for BJs made up of pure d-wave superconductors with relevant parameters. The main CDW-effects were found to be the appearance of new CVC peculiarities and the loss of CVC symmetry with respect to the V-sign. Tunnel directionality was shown to be one of the key factors in the formation of [Formula: see text] dependences. In particular, the orientation of electrodes with respect to the current channel becomes very important. As a result, [Formula: see text] can acquire a large variety of forms similar to those for tunnel junctions between superconductors with s-wave, d-wave, and mixed symmetry of their order parameters. The diversity of peculiarities is especially striking at finite temperatures. In the case of BJs made up of pure d-wave superconductors, the resulting CVC can include a two-peak gap-driven structure. The results were compared with the experimental BJ data for a number of high-T c oxides. It was shown that the large variety of the observed current-voltage characteristics can be interpreted in the framework of our approach. Thus, quasiparticle tunnel currents in the ab-plane can be used as an additional mean to detect CDWs competing with superconductivity in cuprates or other layered superconductors.
Collapse
Affiliation(s)
- T Ekino
- Hiroshima University, Graduate School of Integrated Arts and Sciences, Higashi-Hiroshima, 739-8521, Japan
| | | | | | | | | |
Collapse
|