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Ge Y, Komijani Y. Emergent Spinon Dispersion and Symmetry Breaking in Two-Channel Kondo Lattices. PHYSICAL REVIEW LETTERS 2022; 129:077202. [PMID: 36018683 DOI: 10.1103/physrevlett.129.077202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Two-channel Kondo lattice serves as a model for a growing family of heavy-fermion compounds. We employ a dynamical large-N technique and go beyond the independent bath approximation to study this model both numerically and analytically using renormalization group ideas. We show that the Kondo effect induces dynamic magnetic correlations that lead to an emergent spinon dispersion. Furthermore, we develop a quantitative framework that interpolates between infinite dimension where the channel-symmetry broken results of mean-field theory are confirmed, and one-dimension where the channel symmetry is restored and a critical fractionalized mode is found.
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Affiliation(s)
- Yang Ge
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Yashar Komijani
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA
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Eschrig M. Spin-polarized supercurrents for spintronics: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:104501. [PMID: 26397456 DOI: 10.1088/0034-4885/78/10/104501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
During the past 15 years a new field has emerged, which combines superconductivity and spintronics, with the goal to pave a way for new types of devices for applications combining the virtues of both by offering the possibility of long-range spin-polarized supercurrents. Such supercurrents constitute a fruitful basis for the study of fundamental physics as they combine macroscopic quantum coherence with microscopic exchange interactions, spin selectivity, and spin transport. This report follows recent developments in the controlled creation of long-range equal-spin triplet supercurrents in ferromagnets and its contribution to spintronics. The mutual proximity-induced modification of order in superconductor-ferromagnet hybrid structures introduces in a natural way such evasive phenomena as triplet superconductivity, odd-frequency pairing, Fulde-Ferrell-Larkin-Ovchinnikov pairing, long-range equal-spin supercurrents, [Formula: see text]-Josephson junctions, as well as long-range magnetic proximity effects. All these effects were rather exotic before 2000, when improvements in nanofabrication and materials control allowed for a new quality of hybrid structures. Guided by pioneering theoretical studies, experimental progress evolved rapidly, and since 2010 triplet supercurrents are routinely produced and observed. We have entered a new stage of studying new phases of matter previously out of our reach, and of merging the hitherto disparate fields of superconductivity and spintronics to a new research direction: super-spintronics.
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Affiliation(s)
- Matthias Eschrig
- Department of Physics, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, UK
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Yoo G, Park J, Lee SSB, Sim HS. Anisotropic charge Kondo effect in a triple quantum dot. PHYSICAL REVIEW LETTERS 2014; 113:236601. [PMID: 25526143 DOI: 10.1103/physrevlett.113.236601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Indexed: 06/04/2023]
Abstract
We predict that an anisotropic charge Kondo effect appears in a triple quantum dot, when the system has twofold degenerate ground states of (1,1,0) and (0,0,1) charge configurations. Using bosonization and refermionization methods, we find that at low temperature the system has the two different phases of massive charge fluctuations between the two charge configurations and vanishing fluctuations, which are equivalent with the Kondo-screened and ferromagnetic phases of the anisotropic Kondo model, respectively. The phase transition is identifiable by electron conductance measurement, offering the possibility of experimentally exploring the anisotropic Kondo model. Our charge Kondo effect has a similar origin to that in a negative-U Anderson impurity.
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Affiliation(s)
- Gwangsu Yoo
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Jinhong Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - S-S B Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - H-S Sim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
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Hoshino S, Kuramoto Y. Superconductivity of composite particles in a two-channel Kondo lattice. PHYSICAL REVIEW LETTERS 2014; 112:167204. [PMID: 24815667 DOI: 10.1103/physrevlett.112.167204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Indexed: 06/03/2023]
Abstract
Emergence of odd-frequency s-wave superconductivity is demonstrated in the two-channel Kondo lattice by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. Around half filling of the conduction bands, divergence of an odd-frequency pairing susceptibility is found, which signals instability toward the superconductivity. The corresponding order parameter is equivalent to a staggered composite-pair amplitude with even frequencies, which involves both localized spins and conduction electrons. A model wave function is constructed for the composite order with the use of symmetry operations such as charge conjugation and channel rotations. Given a certain asymmetry of the conduction bands, another s-wave superconductivity is found that has a uniform order parameter. The Kondo effect in the presence of two channels is essential for both types of unconventional superconductivity.
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Affiliation(s)
- Shintaro Hoshino
- Department of Basic Science, The University of Tokyo, Meguro, Tokyo 153-8902, Japan
| | - Yoshio Kuramoto
- Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan
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Ong TT, Coleman P. Local quantum criticality of an iron-pnictide tetrahedron. PHYSICAL REVIEW LETTERS 2012; 108:107201. [PMID: 22463447 DOI: 10.1103/physrevlett.108.107201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Indexed: 05/31/2023]
Abstract
Motivated by the close correlation between transition temperature (T(c)) and the tetrahedral bond angle of the As-Fe-As layer observed in the iron-based superconductors, we study the interplay between spin and orbital physics of an isolated iron-arsenide tetrahedron embedded in a metallic environment. Whereas the spin-Kondo effect is suppressed to low temperatures by Hund's coupling, the orbital degrees of freedom are expected to quantum mechanically quench at high temperatures, giving rise to an overscreened, non-Fermi liquid ground state. Translated into a dense environment, this critical state may play an important role in the superconductivity of these materials.
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Affiliation(s)
- T Tzen Ong
- Center for Materials Theory, Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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Caprara S, Di Castro C, Fratini S, Grilli M. Anomalous optical absorption in the normal state of overdoped cuprates near the charge-ordering instability. PHYSICAL REVIEW LETTERS 2002; 88:147001. [PMID: 11955168 DOI: 10.1103/physrevlett.88.147001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2001] [Indexed: 05/23/2023]
Abstract
We argue that the hump observed in the optical conductivity at or below a few hundreds of cm(-1), in overdoped cuprates such as the electron-doped Nd(2-x)Ce(x)CuO(4-y) at x > or approximately equal to 0.15 and the hole-doped Bi2Sr2CuO6 and La2-xSrxCuO4, cannot be accounted for within a single-fluid description. We propose instead an interpretation based on the direct excitation of charge collective modes, which become nearly critical in the proximity to a charge-ordering instability. Their critical character entails a peculiar temperature dependence and a pseudoscaling form of the optical spectra, which agree with the experimental data.
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Affiliation(s)
- S Caprara
- INFM and SMC, Unità di Roma 1, and Dipartimento di Fisica-Università di Roma "La Sapienza," Piazzale Aldo Moro 2, I-00185 Roma, Italy
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Bogdanov PV, Lanzara A, Kellar SA, Zhou XJ, Lu ED, Zheng WJ, Gu G, Shimoyama J, Kishio K, Ikeda H, Yoshizaki R, Hussain Z, Shen ZX. Evidence for an energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8. PHYSICAL REVIEW LETTERS 2000; 85:2581-2584. [PMID: 10978112 DOI: 10.1103/physrevlett.85.2581] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/1999] [Indexed: 05/23/2023]
Abstract
Quasiparticle dispersion in Bi2Sr2CaCu2O8 is investigated with improved angular resolution as a function of temperature and doping. Unlike the linear dispersion predicted by the band calculation, the data show a sharp break in dispersion at 50+/-15 meV binding energy where the velocity changes by a factor of 2 or more. This change provides an energy scale in the quasiparticle self-energy. This break in dispersion is evident at and away from the d-wave node line, but the magnitude of the dispersion change decreases with temperature and with increasing doping.
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Affiliation(s)
- PV Bogdanov
- Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA
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Egger R, Schoeller H. RKKY interaction and Kondo screening cloud for strongly correlated electrons. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:16337-16340. [PMID: 9985738 DOI: 10.1103/physrevb.54.16337] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ye J. Emery-Kivelson Line and Universality of Wilson Ratio of Spin Anisotropic Kondo Model. PHYSICAL REVIEW LETTERS 1996; 77:3224-3227. [PMID: 10062165 DOI: 10.1103/physrevlett.77.3224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Zachar O, Kivelson SA, Emery VJ. Exact Results for a 1D Kondo Lattice from Bosonization. PHYSICAL REVIEW LETTERS 1996; 77:1342-1345. [PMID: 10063052 DOI: 10.1103/physrevlett.77.1342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Quijada MA, Tanner DB, Chou FC, Johnston DC, Cheong S. Optical properties of single-crystal La2CuO4+ delta. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:15485-15503. [PMID: 9980906 DOI: 10.1103/physrevb.52.15485] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Fabrizio M, Gogolin AO, Nozières P. Anderson-Yuval approach to the multichannel Kondo problem. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:16088-16097. [PMID: 9978590 DOI: 10.1103/physrevb.51.16088] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Schiller A, Ingersent K. Exact results for the Kondo effect in a Luttinger liquid. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:4676-4679. [PMID: 9979324 DOI: 10.1103/physrevb.51.4676] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ralph DC, Buhrman RA. Kondo scattering from atomic two-level tunneling systems in metals: Enhanced conductance, critical-bias transitions, and the non-Fermi-liquid electronic state. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:3554-3568. [PMID: 9979165 DOI: 10.1103/physrevb.51.3554] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Hettler MH, Kroha J, Hershfield S. Nonlinear conductance for the two channel Anderson model. PHYSICAL REVIEW LETTERS 1994; 73:1967-1970. [PMID: 10056934 DOI: 10.1103/physrevlett.73.1967] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Ralph DC, Ludwig AW, Buhrman RA. 2-channel Kondo scaling in conductance signals from 2 level tunneling systems. PHYSICAL REVIEW LETTERS 1994; 72:1064-1067. [PMID: 10056608 DOI: 10.1103/physrevlett.72.1064] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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