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Superconductivity and the Jahn–Teller Polaron. CONDENSED MATTER 2022. [DOI: 10.3390/condmat7010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this article, we review the essential properties of high-temperature superconducting cuprates, which are unconventional isotope effects, heterogeneity, and lattice responses. Since their discovery was based on ideas stemming from Jahn–Teller polarons, their special role, together with the Jahn–Teller effect itself, is discussed in greater detail. We conclude that the underlying physics of cuprates cannot stem from purely electronic mechanisms, but that the intricate interaction between lattice and charge is at its origin.
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From SrTiO3 to Cuprates and Back to SrTiO3: A Way Along Alex Müller’s Scientific Career. CONDENSED MATTER 2020. [DOI: 10.3390/condmat6010002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
K.A. Müller took a long route in science leaving many traces and imprints, which have been and are still today initiations for further research activities. We “walk” along this outstanding path but are certainly not able to provide a complete picture of it, since the way was not always straight, often marked by unintended detours, which had novel impact on the international research society.
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Probing Phase Separation and Local Lattice Distortions in Cuprates by Raman Spectroscopy. CONDENSED MATTER 2019. [DOI: 10.3390/condmat4040087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It is generally accepted that high temperature superconductors emerge when extra carriers are introduced in the parent state, which looks like a Mott insulator. Competition of the order parameters drives the system into a poorly defined pseudogap state before acquiring the normal Fermi liquid behavior with further doping. Within the low doping level, the system has the tendency for mesoscopic phase separation, which seems to be a general characteristic in all high Tc compounds, but also in the materials of colossal magnetoresistance or the relaxor ferroelectrics. In all these systems, metastable phases can be created by tuning physical variables, such as doping or pressure, and the competing order parameters can drive the compound to various states. Structural instabilities are expected at critical points and Raman spectroscopy is ideal for detecting them, since it is a very sensitive technique for detecting small lattice modifications and instabilities. In this article, phase separation and lattice distortions are examined on the most characteristic family of high temperature superconductors, the cuprates. The effect of doping or atomic substitutions on cuprates is examined concerning the induced phase separation and hydrostatic pressure for activating small local lattice distortions at the edge of lattice instability.
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Guguchia Z, Kerelsky A, Edelberg D, Banerjee S, von Rohr F, Scullion D, Augustin M, Scully M, Rhodes DA, Shermadini Z, Luetkens H, Shengelaya A, Baines C, Morenzoni E, Amato A, Hone JC, Khasanov R, Billinge SJL, Santos E, Pasupathy AN, Uemura YJ. Magnetism in semiconducting molybdenum dichalcogenides. SCIENCE ADVANCES 2018; 4:eaat3672. [PMID: 30588488 PMCID: PMC6303124 DOI: 10.1126/sciadv.aat3672] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 11/19/2018] [Indexed: 05/30/2023]
Abstract
Transition metal dichalcogenides (TMDs) are interesting for understanding the fundamental physics of two-dimensional (2D) materials as well as for applications to many emerging technologies, including spin electronics. Here, we report the discovery of long-range magnetic order below T M = 40 and 100 K in bulk semiconducting TMDs 2H-MoTe2 and 2H-MoSe2, respectively, by means of muon spin rotation (μSR), scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. The μSR measurements show the presence of large and homogeneous internal magnetic fields at low temperatures in both compounds indicative of long-range magnetic order. DFT calculations show that this magnetism is promoted by the presence of defects in the crystal. The STM measurements show that the vast majority of defects in these materials are metal vacancies and chalcogen-metal antisites, which are randomly distributed in the lattice at the subpercent level. DFT indicates that the antisite defects are magnetic with a magnetic moment in the range of 0.9 to 2.8 μB. Further, we find that the magnetic order stabilized in 2H-MoTe2 and 2H-MoSe2 is highly sensitive to hydrostatic pressure. These observations establish 2H-MoTe2 and 2H-MoSe2 as a new class of magnetic semiconductors and open a path to studying the interplay of 2D physics and magnetism in these interesting semiconductors.
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Affiliation(s)
- Z. Guguchia
- Department of Physics, Columbia University, New York, NY 10027, USA
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - A. Kerelsky
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - D. Edelberg
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - S. Banerjee
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - F. von Rohr
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - D. Scullion
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, UK
| | - M. Augustin
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, UK
| | - M. Scully
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, UK
| | - D. A. Rhodes
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - Z. Shermadini
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - H. Luetkens
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - A. Shengelaya
- Department of Physics, Tbilisi State University, Chavchavadze 3, GE-0128 Tbilisi, Georgia
- Andronikashvili Institute of Physics of I. Javakhishvili Tbilisi State University, Tamarashvili str. 6, 0177 Tbilisi, Georgia
| | - C. Baines
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - E. Morenzoni
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - A. Amato
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - J. C. Hone
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - R. Khasanov
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - S. J. L. Billinge
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - E. Santos
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, UK
| | - A. N. Pasupathy
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - Y. J. Uemura
- Department of Physics, Columbia University, New York, NY 10027, USA
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Guguchia Z, Roessli B, Khasanov R, Amato A, Pomjakushina E, Conder K, Uemura YJ, Tranquada JM, Keller H, Shengelaya A. Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates. PHYSICAL REVIEW LETTERS 2017; 119:087002. [PMID: 28952761 DOI: 10.1103/physrevlett.119.087002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Indexed: 06/07/2023]
Abstract
We report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x≈1/8, the spin-stripe ordering temperature T_{so} decreases linearly with Zn doping y and disappears at y≈4%, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO_{2} plane. Moreover, T_{so} is suppressed by Zn in the same manner as the superconducting transition temperature T_{c} for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent on intertwining with superconducting correlations.
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Affiliation(s)
- Z Guguchia
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - B Roessli
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - R Khasanov
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - A Amato
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - E Pomjakushina
- Laboratory for scientific developments and novel materials, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - K Conder
- Laboratory for scientific developments and novel materials, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Y J Uemura
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - J M Tranquada
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - H Keller
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - A Shengelaya
- Department of Physics, Tbilisi State University, Chavchavadze 3, GE-0128 Tbilisi, Georgia
- Andronikashvili Institute of Physics, I. Javakhishvili Tbilisi State University, Tamarashvili Street 6, 0177 Tbilisi, Georgia
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