1
|
Massee F, Huang YK, Aprili M. Atomic manipulation of the gap in Bi 2Sr 2CaCu 2O 8+x. Science 2020; 367:68-71. [PMID: 31896712 DOI: 10.1126/science.aaw7964] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 11/07/2019] [Indexed: 11/02/2022]
Abstract
Single-atom manipulation within doped correlated electron systems could help disentangle the influence of dopants, structural defects, and crystallographic characteristics on local electronic states. Unfortunately, the high diffusion barrier in these materials prevents conventional manipulation techniques. Here, we demonstrate the possibility to reversibly manipulate select sites in the optimally doped high-temperature superconductor Bi2Sr2CaCu2O8+x using the local electric field of the tip of a scanning tunneling microscope. We show that upon shifting individual Bi atoms at the surface, the spectral gap associated with superconductivity is seen to reversibly change by as much as 15 milli-electron volts (on average ~5% of the total gap size). Our toy model, which captures all observed characteristics, suggests that the electric field induces lateral movement of local pairing potentials in the CuO2 plane.
Collapse
Affiliation(s)
- F Massee
- Laboratoire de Physique des Solides, CNRS UMR 8502, Bâtiment 510, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.
| | - Y K Huang
- Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - M Aprili
- Laboratoire de Physique des Solides, CNRS UMR 8502, Bâtiment 510, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| |
Collapse
|
2
|
Massee F, Huang YK, Golden MS, Aprili M. Noisy defects in the high-T c superconductor Bi 2Sr 2CaCu 2O 8+x. Nat Commun 2019; 10:544. [PMID: 30710086 PMCID: PMC6358600 DOI: 10.1038/s41467-019-08518-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/16/2019] [Indexed: 11/18/2022] Open
Abstract
Dopants and impurities are crucial in shaping the ground state of host materials: semiconducting technology is based on their ability to donate or trap electrons, and they can even be used to transform insulators into high temperature superconductors. Due to limited time resolution, most atomic-scale studies of the latter materials focussed on the effect of dopants on the electronic properties averaged over time. Here, by using atomic-scale current-noise measurements in optimally doped Bi2Sr2CaCu2O8+x, we visualize sub-nanometre sized objects where the tunnelling current-noise is enhanced by at least an order of magnitude. We show that these objects are previously undetected oxygen dopants whose ionization and local environment leads to unconventional charge dynamics resulting in correlated tunnelling events. The ionization of these dopants opens up new routes to dynamically control doping at the atomic scale, enabling the direct visualization of local charging on e.g. high-Tc superconductivity. The effects of dopants in high-temperature superconductors on the surrounding electronic structure give insights into their unconventional microscopic behaviour. Here the authors find a new class of defects that they identify as oxygen dopants whose ionization and local environment induce unusual atomic-scale charge dynamics.
Collapse
Affiliation(s)
- F Massee
- Laboratoire de Physique des Solides (CNRS UMR 8502), Bâtiment 510, Université Paris-Sud/Université Paris-Saclay, 91405, Orsay, France.
| | - Y K Huang
- Institute of Physics, University of Amsterdam, 1098 XH, Amsterdam, The Netherlands
| | - M S Golden
- Institute of Physics, University of Amsterdam, 1098 XH, Amsterdam, The Netherlands
| | - M Aprili
- Laboratoire de Physique des Solides (CNRS UMR 8502), Bâtiment 510, Université Paris-Sud/Université Paris-Saclay, 91405, Orsay, France
| |
Collapse
|
3
|
Kreisel A, Choubey P, Berlijn T, Ku W, Andersen BM, Hirschfeld PJ. Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates. PHYSICAL REVIEW LETTERS 2015; 114:217002. [PMID: 26066452 DOI: 10.1103/physrevlett.114.217002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Indexed: 06/04/2023]
Abstract
We apply a recently developed method combining first principles based Wannier functions with solutions to the Bogoliubov-de Gennes equations to the problem of interpreting STM data in cuprate superconductors. We show that the observed images of Zn on the surface of Bi_{2}Sr_{2}CaCu_{2}O_{8} can only be understood by accounting for the tails of the Cu Wannier functions, which include significant weight on apical O sites in neighboring unit cells. This calculation thus puts earlier crude "filter" theories on a microscopic foundation and solves a long-standing puzzle. We then study quasiparticle interference phenomena induced by out-of-plane weak potential scatterers, and show how patterns long observed in cuprates can be understood in terms of the interference of Wannier functions above the surface. Our results show excellent agreement with experiment and enable a better understanding of novel phenomena in the cuprates via STM imaging.
Collapse
Affiliation(s)
- A Kreisel
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Peayush Choubey
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
| | - T Berlijn
- Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W Ku
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
| |
Collapse
|
4
|
Fritz L, Vojta M. The physics of Kondo impurities in graphene. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:032501. [PMID: 23411583 DOI: 10.1088/0034-4885/76/3/032501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This article summarizes our understanding of the Kondo effect in graphene, primarily from a theoretical perspective. We shall describe different ways to create magnetic moments in graphene, either by adatom deposition or via defects. For dilute moments, the theoretical description is in terms of effective Anderson or Kondo impurity models coupled to graphene's Dirac electrons. We shall discuss in detail the physics of these models, including their quantum phase transitions and the effect of carrier doping, and confront this with existing experimental data. Finally, we will point out connections to other quantum impurity problems, e.g., in unconventional superconductors, topological insulators, and quantum spin liquids.
Collapse
Affiliation(s)
- Lars Fritz
- Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany.
| | | |
Collapse
|
5
|
Hashimoto M, He RH, Testaud JP, Meevasana W, Moore RG, Lu DH, Yoshida Y, Eisaki H, Devereaux TP, Hussain Z, Shen ZX. Reaffirming the d(x2-y2) superconducting gap using the autocorrelation angle-resolved photoemission spectroscopy of Bi1.5Pb0.55Sr1.6La0.4CuO(6+δ). PHYSICAL REVIEW LETTERS 2011; 106:167003. [PMID: 21599403 DOI: 10.1103/physrevlett.106.167003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Indexed: 05/30/2023]
Abstract
Knowledge of the gap function is important to understand the pairing mechanism for high-temperature (T(c)) superconductivity. However, Fourier transform scanning tunneling spectroscopy (FT STS) and angle-resolved photoemission spectroscopy (ARPES) in the cuprates have reported contradictory gap functions, with FT-STS results deviating strongly from a canonical d(x2-y2) form. By applying an "octet model" analysis to autocorrelation ARPES, we reveal that a contradiction occurs because the octet model does not consider the effects of matrix elements and the pseudogap. This reaffirms the canonical d(x2-y2) superconducting gap around the node, which can be directly determined from ARPES. Further, our study suggests that the FT-STS reported fluctuating superconductivity around the node at far above T(c) is not necessary to explain the existence of the quasiparticle interference at low energy.
Collapse
Affiliation(s)
- M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Nieminen J, Lin H, Markiewicz RS, Bansil A. Origin of the electron-hole asymmetry in the scanning tunneling spectrum of the high-temperature Bi2Sr2CaCu2O8+delta superconductor. PHYSICAL REVIEW LETTERS 2009; 102:037001. [PMID: 19257381 DOI: 10.1103/physrevlett.102.037001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2008] [Indexed: 05/27/2023]
Abstract
We have developed a material specific theoretical framework for modeling scanning tunneling spectroscopy (STS) of high-temperature superconducting materials in the normal as well as the superconducting state. Results for Bi2Sr2CaCu2O8+delta (Bi2212) show clearly that the tunneling process strongly modifies the STS spectrum from the local density of states of the dx2-y2 orbital of Cu. The dominant tunneling channel to the surface Bi involves the dx2-y2 orbitals of the four neighboring Cu atoms. In accord with experimental observations, the computed spectrum displays a remarkable asymmetry between the processes of electron injection and extraction, which arises from contributions of Cu dz2 and other orbitals to the tunneling current.
Collapse
Affiliation(s)
- Jouko Nieminen
- Institute of Physics, Tampere University of Technology, P.O. Box 692, 33101 Tampere, Finland.
| | | | | | | |
Collapse
|
7
|
Chen Y, Rice TM, Zhang FC. Rotational symmetry breaking in the ground state of sodium-doped cuprate superconductors. PHYSICAL REVIEW LETTERS 2006; 97:237004. [PMID: 17280234 DOI: 10.1103/physrevlett.97.237004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Indexed: 05/13/2023]
Abstract
We use an extended t-J model to study a single hole bound to a Na+ acceptor in Ca2-xNaxCuO2Cl2. For parameters suitable to cuprates, the ground state has a twofold degeneracy, corresponding to even (odd) reflection symmetry around the x (y) axes. The conductance pattern of the broken symmetry state is anisotropic as the tip of a tunneling microscope scans above the Cu-O-Cu bonds along the x (y) axes. This anisotropy is pronounced at lower voltages but reduced at higher voltages. Our theory agrees qualitatively with recent data of scanning tunneling microscopy showing broken local rotational symmetry.
Collapse
Affiliation(s)
- Yan Chen
- Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | | | | |
Collapse
|
8
|
Andersen BM, Melikyan A, Nunner TS, Hirschfeld PJ. Andreev states near short-ranged pairing potential impurities. PHYSICAL REVIEW LETTERS 2006; 96:097004. [PMID: 16606300 DOI: 10.1103/physrevlett.96.097004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Indexed: 05/08/2023]
Abstract
We study Andreev states near atomic scale modulations in the pairing potential in both s- and d-wave superconductors with short coherence lengths. For a moderate reduction of the local gap, the states exist only close to the gap edge. If one allows for local sign changes of the order parameter, however, resonances can occur at energies close to the Fermi level. The local density of states (LDOS) around such pairing potential defects strongly resembles the patterns observed by tunneling measurements around Zn impurities in Bi2Sr2CaCu2O8+x (BSCCO). We discuss how this phase impurity model of the Zn LDOS pattern can be distinguished from other proposals experimentally.
Collapse
Affiliation(s)
- Brian M Andersen
- Department of Physics, University of Florida, Gainesville, Florida 32611-8440, USA
| | | | | | | |
Collapse
|
9
|
McElroy K, Gweon GH, Zhou SY, Graf J, Uchida S, Eisaki H, Takagi H, Sasagawa T, Lee DH, Lanzara A. Elastic scattering susceptibility of the high temperature superconductor Bi2Sr2CaCu2O(8+delta): a comparison between real and momentum space photoemission spectroscopies. PHYSICAL REVIEW LETTERS 2006; 96:067005. [PMID: 16606036 DOI: 10.1103/physrevlett.96.067005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Indexed: 05/08/2023]
Abstract
The joint density of states of Bi2Sr2CaCu2O(8+delta) is calculated by evaluating the autocorrelation of the single particle spectral function A(k, omega) measured from angle resolved photoemission spectroscopy (ARPES). These results are compared with Fourier transformed (FT) conductance modulations measured by scanning tunneling microscopy (STM). Good agreement between the two experimental probes is found for two different doping values examined. In addition, by comparing the FT-STM results to the autocorrelated ARPES spectra with different photon polarization, new insight on the form of the STM matrix elements is obtained. This shines new light on unsolved mysteries in the tunneling data.
Collapse
Affiliation(s)
- K McElroy
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Zhu JX, Sun J, Si Q, Balatsky AV. Effects of a collective spin resonance mode on the scanning tunneling microscopy spectra of d-wave superconductors. PHYSICAL REVIEW LETTERS 2004; 92:017002. [PMID: 14754011 DOI: 10.1103/physrevlett.92.017002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2003] [Indexed: 05/24/2023]
Abstract
A high-energy spin resonance mode is known to exist in many high-temperature superconductors. Motivated by recent scanning tunneling microscopy experiments in superconducting Bi(2)Sr(2)CaCu(2)O(8+delta), we study the effects of this resonance mode on the local density of states (LDOS). The coupling between the electrons in a d-wave superconductor and the resonance mode produces high-energy peaks in the LDOS, which displays a two-unit-cell periodic modulation around a nonmagnetic impurity. This suggests a new means to not only detect the dynamical spin collective mode but also study its coupling to electronic excitations.
Collapse
Affiliation(s)
- Jian-Xin Zhu
- Theoretical Division, MS B262, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | | | | |
Collapse
|
11
|
Morr DK, Balatsky AV. Impurities and quantum interference in the chains of YBa2Cu3O6+x. PHYSICAL REVIEW LETTERS 2003; 90:067005. [PMID: 12633321 DOI: 10.1103/physrevlett.90.067005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2001] [Indexed: 05/24/2023]
Abstract
Motivated by recent experiments, we study the electronic structure near impurities in the chains of YBa2Cu3O6+x. Using a model of proximity induced chain superconductivity, we show that a resonance state in the chain density of states is induced only by a magnetic impurity. The spatial form of the resonance reflects the particle-hole nature of chain superconductivity and therefore distinguishes it from other broken symmetry phases. Because of quantum interference effects between impurities, the chains can undergo a quantum phase transition into a polarized state.
Collapse
Affiliation(s)
- Dirk K Morr
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | | |
Collapse
|
12
|
Moradian R, Györffy BL, Annett JF. Impurity bound states in disordered d-wave superconductors. PHYSICAL REVIEW LETTERS 2002; 89:287002. [PMID: 12513174 DOI: 10.1103/physrevlett.89.287002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2002] [Indexed: 05/24/2023]
Abstract
Recent STM experiments on Bi2Sr2Ca2Cu3O10 observed sharp bound states associated with Zn and Ni impurities, as previously predicted theoretically. Here we extend the theory to the case of a finite concentration of impurities. Using the nonlocal coherent potential approximation, we show that the resonance peak both broadens and shifts as a function of impurity concentration.
Collapse
|
13
|
Misra S, Oh S, Hornbaker DJ, DiLuccio T, Eckstein JN, Yazdani A. Atomic scale imaging and spectroscopy of a CuO(2) plane at the surface of Bi(2)Sr(2)CaCu(2)O(8+delta). PHYSICAL REVIEW LETTERS 2002; 89:087002. [PMID: 12190493 DOI: 10.1103/physrevlett.89.087002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2002] [Indexed: 05/23/2023]
Abstract
We have used a scanning tunneling microscope to demonstrate that a single CuO2 plane can form a stable and atomically ordered layer at the surface of Bi(2)Sr(2)CaCu(2)O(8+delta). In contrast to previous studies on high-T(c) surfaces, the CuO2-terminated surface exhibits a strongly suppressed tunneling conductance at low voltages. We consider a number of different explanations for this phenomena and propose that it may be caused by how the orbital symmetry of the CuO2 plane's electronic states affects the tunneling process.
Collapse
Affiliation(s)
- S Misra
- Department of Physics and Fredrick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | | | | | | | | | | |
Collapse
|