1
|
Zou C, Choi J, Li Q, Ye S, Yin C, Garcia-Fernandez M, Agrestini S, Qiu Q, Cai X, Xiao Q, Zhou X, Zhou KJ, Wang Y, Peng Y. Evolution from a charge-ordered insulator to a high-temperature superconductor in Bi 2Sr 2(Ca,Dy)Cu 2O 8+δ. Nat Commun 2024; 15:7739. [PMID: 39231956 PMCID: PMC11375163 DOI: 10.1038/s41467-024-52124-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 08/26/2024] [Indexed: 09/06/2024] Open
Abstract
How Cooper pairs form and condense has been the main challenge in the physics of copper-oxide high-temperature superconductors. Great efforts have been made in the 'underdoped' region of the phase diagram, through doping a Mott insulator or cooling a strange metal. However, there is still no consensus on how superconductivity emerges when electron-electron correlations dominate and the Fermi surface is missing. To address this issue, here we carry out high-resolution resonant inelastic X-ray scattering and scanning tunneling microscopy studies on prototype cuprates Bi2Sr2Ca0.6Dy0.4Cu2O8+δ near the onset of superconductivity, combining bulk and surface, momentum- and real-space information. We show that an incipient charge order exists in the antiferromagnetic regime down to 0.04 holes per CuO2 unit, entangled with a particle-hole asymmetric pseudogap. The charge order induces an intensity anomaly in the bond-buckling phonon branch, which exhibits an abrupt increase once the system enters the superconducting dome. Our results suggest that the Cooper pairs grow out of a charge-ordered insulating state, and then condense accompanied by an enhanced interplay between charge excitations and electron-phonon coupling.
Collapse
Affiliation(s)
- Changwei Zou
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Jaewon Choi
- Diamond Light Source, Harwell Campus, Didcot, UK
| | - Qizhi Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- Shenzhen Pinghu Laboratory, Building C, Chinese Sciences Vally, Industrial Park (iBT), Shenzhen, China
| | - Shusen Ye
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Chaohui Yin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | | | | | - Qingzheng Qiu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Xinqiang Cai
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Qian Xiao
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot, UK
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
- Frontier Science Center for Quantum Information, Beijing, China.
| | - Yingying Peng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
| |
Collapse
|
2
|
Dong Z, Huo M, Li J, Li J, Li P, Sun H, Gu L, Lu Y, Wang M, Wang Y, Chen Z. Visualization of oxygen vacancies and self-doped ligand holes in La 3Ni 2O 7-δ. Nature 2024; 630:847-852. [PMID: 38839959 DOI: 10.1038/s41586-024-07482-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 04/29/2024] [Indexed: 06/07/2024]
Abstract
The recent discovery of superconductivity in La3Ni2O7-δ under high pressure with a transition temperature around 80 K (ref. 1) has sparked extensive experimental2-6 and theoretical efforts7-12. Several key questions regarding the pairing mechanism remain to be answered, such as the most relevant atomic orbitals and the role of atomic deficiencies. Here we develop a new, energy-filtered, multislice electron ptychography technique, assisted by electron energy-loss spectroscopy, to address these critical issues. Oxygen vacancies are directly visualized and are found to primarily occupy the inner apical sites, which have been proposed to be crucial to superconductivity13,14. We precisely determine the nanoscale stoichiometry and its correlation to the oxygen K-edge spectra, which reveals a significant inhomogeneity in the oxygen content and electronic structure within the sample. The spectroscopic results also reveal that stoichiometric La3Ni2O7 has strong charge-transfer characteristics, with holes that are self-doped from Ni sites into O sites. The ligand holes mainly reside on the inner apical O and the planar O, whereas the density on the outer apical O is negligible. As the concentration of O vacancies increases, ligand holes on both sites are simultaneously annihilated. These observations will assist in further development and understanding of superconducting nickelate materials. Our imaging technique for quantifying atomic deficiencies can also be widely applied in materials science and condensed-matter physics.
Collapse
Affiliation(s)
- Zehao Dong
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Mengwu Huo
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Sun Yat-Sen University, Guangzhou, China
| | - Jie Li
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, China
| | - Jingyuan Li
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Sun Yat-Sen University, Guangzhou, China
| | - Pengcheng Li
- School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Hualei Sun
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Sun Yat-Sen University, Guangzhou, China
- School of Science, Sun Yat-Sen University, Shenzhen, China
| | - Lin Gu
- School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Yi Lu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Meng Wang
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, China.
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Sun Yat-Sen University, Guangzhou, China.
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
- New Cornerstone Science Laboratory, Frontier Science Center for Quantum Information, Beijing, China.
- Hefei National Laboratory, Hefei, China.
| | - Zhen Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
3
|
Wang S, Kennedy N, Fujita K, Uchida SI, Eisaki H, Johnson PD, Davis JCS, O'Mahony SM. Discovery of orbital ordering in Bi 2Sr 2CaCu 2O 8+x. NATURE MATERIALS 2024; 23:492-498. [PMID: 38438620 PMCID: PMC10990940 DOI: 10.1038/s41563-024-01817-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 01/22/2024] [Indexed: 03/06/2024]
Abstract
The primordial ingredient of cuprate superconductivity is the CuO2 unit cell. Theories usually concentrate on the intra-atom Coulombic interactions dominating the 3d9 and 3d10 configurations of each copper ion. However, if Coulombic interactions also occur between electrons of the 2p6 orbitals of each planar oxygen atom, spontaneous orbital ordering may split their energy levels. This long-predicted intra-unit-cell symmetry breaking should generate an orbitally ordered phase, for which the charge transfer energy ε separating the 2p6 and 3d10 orbitals is distinct for the two oxygen atoms. Here we introduce sublattice-resolved ε(r) imaging to CuO2 studies and discover intra-unit-cell rotational symmetry breaking of ε(r). Spatially, this state is arranged in disordered Ising domains of orthogonally oriented orbital order bounded by dopant ions, and within whose domain walls low-energy electronic quadrupolar two-level systems occur. Overall, these data reveal a Q = 0 orbitally ordered state that splits the oxygen energy levels by ~50 meV, in underdoped CuO2.
Collapse
Affiliation(s)
- Shuqiu Wang
- Clarendon Laboratory, University of Oxford, Oxford, UK.
- Department of Physics, Cornell University, Ithaca, NY, USA.
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, UK.
| | - Niall Kennedy
- Clarendon Laboratory, University of Oxford, Oxford, UK
- School of Physics, University College Cork, Cork, Ireland
| | - Kazuhiro Fujita
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | | | - Hiroshi Eisaki
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Peter D Johnson
- Clarendon Laboratory, University of Oxford, Oxford, UK
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - J C Séamus Davis
- Clarendon Laboratory, University of Oxford, Oxford, UK.
- Department of Physics, Cornell University, Ithaca, NY, USA.
- School of Physics, University College Cork, Cork, Ireland.
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
| | | |
Collapse
|
4
|
Wang Z, Zou C, Lin C, Luo X, Yan H, Yin C, Xu Y, Zhou X, Wang Y, Zhu J. Correlating the charge-transfer gap to the maximum transition temperature in Bi 2Sr 2Ca n-1Cu nO 2n+4+δ. Science 2023; 381:227-231. [PMID: 37440647 DOI: 10.1126/science.add3672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/06/2023] [Indexed: 07/15/2023]
Abstract
As the number of CuO2 layers, n, in each unit cell of a cuprate family increases, the maximum transition temperature (Tc,max) exhibits a universal bell-shaped curve with a peak at n = 3. The microscopic mechanism of this trend remains elusive. In this study, we used advanced electron microscopy to image the atomic structure of cuprates in the Bi2Sr2Can-1CunO2n+4+δ family with 1 ≤ n ≤ 9; the evolution of the charge-transfer gap size (Δ) with n can be measured simultaneously. We determined that the n dependence of Δ follows an inverted bell-shaped curve with the minimum Δ value at n = 3. The correlation between Δ, n, and Tc,max may clarify the origin of superconductivity in cuprates.
Collapse
Affiliation(s)
- Zechao Wang
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, P.R. China
- Ji Hua Laboratory, Foshan, Guangdong, P.R. China
| | - Changwei Zou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, P.R. China
| | - Chengtian Lin
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Xiangyu Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Hongtao Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Chaohui Yin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Yong Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, P.R. China
- New Cornerstone Science Laboratory, Frontier Science Center for Quantum Information, Beijing, P.R. China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Yayu Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, P.R. China
- New Cornerstone Science Laboratory, Frontier Science Center for Quantum Information, Beijing, P.R. China
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, P.R. China
- Ji Hua Laboratory, Foshan, Guangdong, P.R. China
| |
Collapse
|
5
|
On the electron pairing mechanism of copper-oxide high temperature superconductivity. Proc Natl Acad Sci U S A 2022; 119:e2207449119. [PMID: 36067325 PMCID: PMC9477408 DOI: 10.1073/pnas.2207449119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The elementary CuO2 plane sustaining cuprate high-temperature superconductivity occurs typically at the base of a periodic array of edge-sharing CuO5 pyramids. Virtual transitions of electrons between adjacent planar Cu and O atoms, occurring at a rate t/ℏ and across the charge-transfer energy gap [Formula: see text], generate "superexchange" spin-spin interactions of energy [Formula: see text] in an antiferromagnetic correlated-insulator state. However, hole doping this CuO2 plane converts this into a very-high-temperature superconducting state whose electron pairing is exceptional. A leading proposal for the mechanism of this intense electron pairing is that, while hole doping destroys magnetic order, it preserves pair-forming superexchange interactions governed by the charge-transfer energy scale [Formula: see text]. To explore this hypothesis directly at atomic scale, we combine single-electron and electron-pair (Josephson) scanning tunneling microscopy to visualize the interplay of [Formula: see text] and the electron-pair density nP in Bi2Sr2CaCu2O8+x. The responses of both [Formula: see text] and nP to alterations in the distance δ between planar Cu and apical O atoms are then determined. These data reveal the empirical crux of strongly correlated superconductivity in CuO2, the response of the electron-pair condensate to varying the charge-transfer energy. Concurrence of predictions from strong-correlation theory for hole-doped charge-transfer insulators with these observations indicates that charge-transfer superexchange is the electron-pairing mechanism of superconductive Bi2Sr2CaCu2O8+x.
Collapse
|
6
|
Wang L, He G, Yang Z, Garcia-Fernandez M, Nag A, Zhou K, Minola M, Tacon ML, Keimer B, Peng Y, Li Y. Paramagnons and high-temperature superconductivity in a model family of cuprates. Nat Commun 2022; 13:3163. [PMID: 35672416 PMCID: PMC9174205 DOI: 10.1038/s41467-022-30918-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Cuprate superconductors have the highest critical temperatures (Tc) at ambient pressure, yet a consensus on the superconducting mechanism remains to be established. Finding an empirical parameter that limits the highest reachable Tc can provide crucial insight into this outstanding problem. Here, in the first two Ruddlesden-Popper members of the model Hg-family of cuprates, which are chemically nearly identical and have the highest Tc among all cuprate families, we use inelastic photon scattering to reveal that the energy of magnetic fluctuations may play such a role. In particular, we observe the single-paramagnon spectra to be nearly identical between the two compounds, apart from an energy scale difference of ~30% which matches their difference in Tc. The empirical correlation between paramagnon energy and maximal Tc is further found to extend to other cuprate families with relatively high Tc’s, hinting at a fundamental connection between them. Finding a parameter that limits the critical temperature of cuprate superconductors can provide crucial insight on the superconducting mechanism. Here, the authors use inelastic photon scattering on two Ruddlesden-Popper members of the model Hg-family of cuprates to reveal that the energy of magnetic fluctuations may play such a role, and suggest that the Cooper pairing is mediated by paramagnons.
Collapse
|
7
|
Weber C. Unifying guiding principles for designing optimized superconductors. Proc Natl Acad Sci U S A 2021; 118:e2115874118. [PMID: 34772818 PMCID: PMC8609548 DOI: 10.1073/pnas.2115874118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Cedric Weber
- Theory and Simulation of Condensed Matter, King's College London, WC2R 2LS London, United Kingdom
| |
Collapse
|
8
|
Kowalski N, Dash SS, Sémon P, Sénéchal D, Tremblay AM. Oxygen hole content, charge-transfer gap, covalency, and cuprate superconductivity. Proc Natl Acad Sci U S A 2021; 118:e2106476118. [PMID: 34593641 PMCID: PMC8501840 DOI: 10.1073/pnas.2106476118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2021] [Indexed: 11/18/2022] Open
Abstract
Experiments have shown that the families of cuprate superconductors that have the largest transition temperature at optimal doping also have the largest oxygen hole content at that doping [D. Rybicki et al., Nat. Commun. 7, 1-6 (2016)]. They have also shown that a large charge-transfer gap [W. Ruan et al., Sci. Bull. (Beijing) 61, 1826-1832 (2016)], a quantity accessible in the normal state, is detrimental to superconductivity. We solve the three-band Hubbard model with cellular dynamical mean-field theory and show that both of these observations follow from the model. Cuprates play a special role among doped charge-transfer insulators of transition metal oxides because copper has the largest covalent bonding with oxygen. Experiments [L. Wang et al., arXiv [Preprint] (2020). https://arxiv.org/abs/2011.05029 (Accessed 10 November 2020)] also suggest that superexchange is at the origin of superconductivity in cuprates. Our results reveal the consistency of these experiments with the above two experimental findings. Indeed, we show that covalency and a charge-transfer gap lead to an effective short-range superexchange interaction between copper spins that ultimately explains pairing and superconductivity in the three-band Hubbard model of cuprates.
Collapse
Affiliation(s)
- Nicolas Kowalski
- Département de physique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Institut quantique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Sidhartha Shankar Dash
- Département de physique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Institut quantique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Patrick Sémon
- Département de physique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - David Sénéchal
- Département de physique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Institut quantique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - André-Marie Tremblay
- Département de physique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada;
- Institut quantique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| |
Collapse
|
9
|
Zegrodnik M, Biborski A, Fidrysiak M, Spałek J. Superconductivity in the three-band model of cuprates: nodal direction characteristics and influence of intersite interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:415601. [PMID: 33264759 DOI: 10.1088/1361-648x/abcff6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
The three-band Emery model is applied to study the selected principal features of thed-wavesuperconducting phase in the copper-based compounds. The electron-electron correlations are taken into account by the use of the diagrammatic expansion of the Guztwiller wave function (DE-GWF method). The nodal Fermi velocity, Fermi momentum, and effective mass are all determined in the paired state and show relatively good agreement with the available experimental data, as well as with the corresponding single-band calculations. Additionally, the influence of the next-nearest neighbor oxygen-oxygen hopping and intersite Coulomb repulsion terms on the superconducting phase is analyzed.
Collapse
Affiliation(s)
- M Zegrodnik
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland
| | - A Biborski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland
| | - M Fidrysiak
- Institute of Theoretical Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
| | - J Spałek
- Institute of Theoretical Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
| |
Collapse
|
10
|
Li H, Ye S, Zhao J, Jin C, Wang Y. Imaging the atomic-scale electronic states induced by a pair of hole dopants in Ca 2CuO 2Cl 2 Mott insulator. Sci Bull (Beijing) 2021; 66:1395-1400. [PMID: 36654365 DOI: 10.1016/j.scib.2021.04.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 01/20/2023]
Abstract
We use scanning tunneling microscopy to visualize the atomic-scale electronic states induced by a pair of hole dopants in Ca2CuO2Cl2 parent Mott insulator of cuprates. We find that when the two dopants approach each other, the transfer of spectral weight from high energy Hubbard band to low energy in-gap state creates a broad peak and nearly V-shaped gap around the Fermi level. The peak position shows a sudden drop at distance around 4 a0 and then remains almost constant. The in-gap states exhibit peculiar spatial distributions depending on the configuration of the two dopants relative to the underlying Cu lattice. These results shed important new lights on the evolution of low energy electronic states when a few holes are doped into parent cuprates.
Collapse
Affiliation(s)
- Haiwei Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Shusen Ye
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Jianfa Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changqing Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Frontier Science Center for Quantum Information, Beijing 100084, China.
| |
Collapse
|
11
|
Momentum-resolved visualization of electronic evolution in doping a Mott insulator. Nat Commun 2021; 12:1356. [PMID: 33649302 PMCID: PMC7921433 DOI: 10.1038/s41467-021-21605-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 01/29/2021] [Indexed: 11/25/2022] Open
Abstract
High temperature superconductivity in cuprates arises from doping a parent Mott insulator by electrons or holes. A central issue is how the Mott gap evolves and the low-energy states emerge with doping. Here we report angle-resolved photoemission spectroscopy measurements on a cuprate parent compound by sequential in situ electron doping. The chemical potential jumps to the bottom of the upper Hubbard band upon a slight electron doping, making it possible to directly visualize the charge transfer band and the full Mott gap region. With increasing doping, the Mott gap rapidly collapses due to the spectral weight transfer from the charge transfer band to the gapped region and the induced low-energy states emerge in a wide energy range inside the Mott gap. These results provide key information on the electronic evolution in doping a Mott insulator and establish a basis for developing microscopic theories for cuprate superconductivity. How a Mott insulating state evolves into a conducting or superconducting state is a central issue in doping a Mott insulator and important to understand the physics in high temperature cuprate superconductors. Here, the authors visualize the electronic structure evolution of a Mott insulator within the full Mott gap region and address the fundamental issues.
Collapse
|
12
|
Wang X, Yuan Y, Xue QK, Li W. Charge ordering in high-temperature superconductors visualized by scanning tunneling microscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:013002. [PMID: 31487703 DOI: 10.1088/1361-648x/ab41c5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since the discovery of stripe order in La1.6-x Nd0.4Sr x CuO4 superconductors in 1995, charge ordering in cuprate superconductors has been intensively studied by various experimental techniques. Among these studies, scanning tunneling microscope (STM) plays an irreplaceable role in determining the real space structures of charge ordering. STM imaging of different families of cuprates over a wide range of doping levels reveal similar checkerboard-like patterns, indicating that such a charge ordered state is likely a ubiquitous and intrinsic characteristic of cuprate superconductors, which may shed light on understanding the mechanism of high-temperature superconductivity. In another class of high-temperature superconductors, iron-based superconductors, STM studies reveal several charge ordered states as well, but their real-space patterns and the interplay with superconductivity are markedly different among different materials. In this paper, we present a brief review on STM studies of charge ordering in these two classes of high-temperature superconductors. Possible origins of charge ordering and its interplay with superconductivity will be discussed.
Collapse
Affiliation(s)
- Xintong Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China. Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China
| | | | | | | |
Collapse
|
13
|
High-temperature superconductivity in monolayer Bi 2Sr 2CaCu 2O 8+δ. Nature 2019; 575:156-163. [PMID: 31666697 DOI: 10.1038/s41586-019-1718-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/23/2019] [Indexed: 11/09/2022]
Abstract
Although copper oxide high-temperature superconductors constitute a complex and diverse material family, they all share a layered lattice structure. This curious fact prompts the question of whether high-temperature superconductivity can exist in an isolated monolayer of copper oxide, and if so, whether the two-dimensional superconductivity and various related phenomena differ from those of their three-dimensional counterparts. The answers may provide insights into the role of dimensionality in high-temperature superconductivity. Here we develop a fabrication process that obtains intrinsic monolayer crystals of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi-2212; here, a monolayer refers to a half unit cell that contains two CuO2 planes). The highest superconducting transition temperature of the monolayer is as high as that of optimally doped bulk. The lack of dimensionality effect on the transition temperature defies expectations from the Mermin-Wagner theorem, in contrast to the much-reduced transition temperature in conventional two-dimensional superconductors such as NbSe2. The properties of monolayer Bi-2212 become extremely tunable; our survey of superconductivity, the pseudogap, charge order and the Mott state at various doping concentrations reveals that the phases are indistinguishable from those in the bulk. Monolayer Bi-2212 therefore displays all the fundamental physics of high-temperature superconductivity. Our results establish monolayer copper oxides as a platform for studying high-temperature superconductivity and other strongly correlated phenomena in two dimensions.
Collapse
|
14
|
Zhao H, Ren Z, Rachmilowitz B, Schneeloch J, Zhong R, Gu G, Wang Z, Zeljkovic I. Charge-stripe crystal phase in an insulating cuprate. NATURE MATERIALS 2019; 18:103-107. [PMID: 30559411 DOI: 10.1038/s41563-018-0243-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
High-temperature (high-Tc) superconductivity in cuprates arises from carrier doping of an antiferromagnetic Mott insulator. This carrier doping leads to the formation of electronic liquid-crystal phases1. The insulating charge-stripe crystal phase is predicted to form when a small density of holes is doped into the charge-transfer insulator state1-3, but this phase is yet to be observed experimentally. Here, we use surface annealing to extend the accessible doping range in Bi-based cuprates and realize the lightly doped charge-transfer insulating state of the cuprate Bi2Sr2CaCu2O8+x. In this insulating state with a charge transfer gap on the order of ~1 eV, our spectroscopic imaging scanning tunnelling microscopy measurements provide strong evidence for a unidirectional charge-stripe order with a commensurate 4a0 period along the Cu-O-Cu bond. Notably, this insulating charge-stripe crystal phase develops before the onset of the pseudogap and formation of the Fermi surface. Our work provides fresh insight into the microscopic origin of electronic inhomogeneity in high-Tc cuprates.
Collapse
Affiliation(s)
- He Zhao
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Zheng Ren
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | | | | | | | - Genda Gu
- Brookhaven National Laboratory, Upton, NY, USA
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Ilija Zeljkovic
- Department of Physics, Boston College, Chestnut Hill, MA, USA.
| |
Collapse
|
15
|
Adler R, Kang CJ, Yee CH, Kotliar G. Correlated materials design: prospects and challenges. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:012504. [PMID: 30138114 DOI: 10.1088/1361-6633/aadca4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The design of correlated materials challenges researchers to combine the maturing, high throughput framework of DFT-based materials design with the rapidly-developing first-principles theory for correlated electron systems. We review the field of correlated materials, distinguishing two broad classes of correlation effects, static and dynamics, and describe methodologies to take them into account. We introduce a material design workflow, and illustrate it via examples in several materials classes, including superconductors, charge ordering materials and systems near an electronically driven metal to insulator transition, highlighting the interplay between theory and experiment with a view towards finding new materials. We review the statistical formulation of the errors of currently available methods to estimate formation energies. We formulate an approach for estimating a lower-bound for the probability of a new compound to form. Correlation effects have to be considered in all the material design steps. These include bridging between structure and property, obtaining the correct structure and predicting material stability. We introduce a post-processing strategy to take them into account.
Collapse
Affiliation(s)
- Ran Adler
- Department of Physics & Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, United States of America
| | | | | | | |
Collapse
|
16
|
Wang Y, Huang EW, Moritz B, Devereaux TP. Magnon Splitting Induced by Charge Transfer in the Three-Orbital Hubbard Model. PHYSICAL REVIEW LETTERS 2018; 120:246401. [PMID: 29956982 DOI: 10.1103/physrevlett.120.246401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Indexed: 06/08/2023]
Abstract
Understanding spin excitations and their connection to unconventional superconductivity have remained central issues since the discovery of cuprates. Direct measurement of the dynamical spin structure factor in the parent compounds can provide key information on important interactions relevant in the doped regime, and variations in the magnon dispersion have been linked closely to differences in crystal structure between families of cuprate compounds. Here, we elucidate the relationship between spin excitations and various controlling factors thought to be significant in high-T_{c} materials by systematically evaluating the dynamical spin structure factor for the three-orbital Hubbard model, revealing differences in the spin dispersion along the Brillouin zone axis and the diagonal. Generally, we find that the absolute energy scale and momentum dependence of the excitations primarily are sensitive to the effective charge-transfer energy, while changes in the on-site Coulomb interactions have little effect on the details of the dispersion. In particular, our result highlights the splitting between spin excitations along the axial and diagonal directions in the Brillouin zone. This splitting decreases with increasing charge-transfer energy and correlates with changes in the apical oxygen position, and general structural variations, for different cuprate families.
Collapse
Affiliation(s)
- Yao Wang
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Edwin W Huang
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Brian Moritz
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA
| | - Thomas P Devereaux
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| |
Collapse
|
17
|
Matt CE, Sutter D, Cook AM, Sassa Y, Månsson M, Tjernberg O, Das L, Horio M, Destraz D, Fatuzzo CG, Hauser K, Shi M, Kobayashi M, Strocov VN, Schmitt T, Dudin P, Hoesch M, Pyon S, Takayama T, Takagi H, Lipscombe OJ, Hayden SM, Kurosawa T, Momono N, Oda M, Neupert T, Chang J. Direct observation of orbital hybridisation in a cuprate superconductor. Nat Commun 2018; 9:972. [PMID: 29511188 PMCID: PMC5840306 DOI: 10.1038/s41467-018-03266-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 02/01/2018] [Indexed: 11/19/2022] Open
Abstract
The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models of the copper–oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation of a two-band structure. This electronic structure, qualitatively consistent with density functional theory, is parametrised by a two-orbital (\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$d_{x^2 - y^2}$$\end{document}dx2-y2 and \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$d_{z^2}$$\end{document}dz2) tight-binding model. We quantify the orbital hybridisation which provides an explanation for the Fermi surface topology and the proximity of the van-Hove singularity to the Fermi level. Our analysis leads to a unification of electronic hopping parameters for single-layer cuprates and we conclude that hybridisation, restraining d-wave pairing, is an important optimisation element for superconductivity. The essential physics of cuprate superconductors is often described by single-band models. Here, Matt et al. report direct observation of a two-band electronic structure in La-based cuprates.
Collapse
Affiliation(s)
- C E Matt
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland. .,Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.
| | - D Sutter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - A M Cook
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Y Sassa
- Department of Physics and Astronomy, Uppsala University, SE-75121, Uppsala, Sweden
| | - M Månsson
- Materials Physics, KTH Royal Institute of Technology, SE-164 40, Kista, Stockholm, Sweden
| | - O Tjernberg
- Materials Physics, KTH Royal Institute of Technology, SE-164 40, Kista, Stockholm, Sweden
| | - L Das
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - M Horio
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - D Destraz
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - C G Fatuzzo
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - K Hauser
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - M Kobayashi
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - S Pyon
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - T Takayama
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - H Takagi
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - O J Lipscombe
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - S M Hayden
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - T Kurosawa
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - N Momono
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan.,Department of Applied Sciences, Muroran Institute of Technology, Muroran, 050-8585, Japan
| | - M Oda
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - T Neupert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
| |
Collapse
|
18
|
Weber C. What controls the critical temperature of high temperature copper oxide superconductors: insights from scanneling tunnelling microscopy. Sci Bull (Beijing) 2017; 62:102-104. [PMID: 36659480 DOI: 10.1016/j.scib.2016.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Cedric Weber
- King's College London, Theory and Simulation of Condensed Matter, The Strand, London WC2R 2LS, UK.
| |
Collapse
|