1
|
The FFLO State in the Dimer Mott Organic Superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br. CRYSTALS 2021. [DOI: 10.3390/cryst11111358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The superconducting phase diagram for a quasi-two-dimensional organic superconductor, κ-(BEDT-TTF)2Cu[N(CN)2]Br, was studied using pulsed magnetic field penetration depth measurements under rotating magnetic fields. At low temperatures, Hc2 was abruptly suppressed even by small tilts of the applied fields owing to the orbital pair-breaking effect. In magnetic fields parallel to the conducting plane, the temperature dependence of the upper critical field Hc2 exhibited an upturn and exceeded the Pauli limit field HP in the lower temperature region. Further analyses with the second derivative of the penetration depth showed an anomaly at 31–32 T, which roughly corresponded to HP. The origin of the anomaly should not be related to the orbital effect, but the paramagnetic effect, which is almost isotropic in organic salts, because it barely depends on the field angle. Based on these results, the observed anomaly is most likely due to the transition between the Bardeen-Cooper-Schrieffer (BCS) and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states. Additionally, we discuss the phase diagram and physical parameters of the transition by comparing them with other FFLO candidates.
Collapse
|
2
|
Nam MS, Ardavan A, Blundell SJ, Schlueter JA. Fluctuating superconductivity in organic molecular metals close to the Mott transition. Nature 2007; 449:584-7. [PMID: 17914392 DOI: 10.1038/nature06182] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 08/15/2007] [Indexed: 11/08/2022]
Abstract
On cooling through the transition temperature T(c) of a conventional superconductor, an energy gap develops as the normal-state charge carriers form Cooper pairs; these pairs form a phase-coherent condensate that exhibits the well-known signatures of superconductivity: zero resistivity and the expulsion of magnetic flux (the Meissner effect). However, in many unconventional superconductors, the formation of the energy gap is not coincident with the formation of the phase-coherent superfluid. Instead, at temperatures above the critical temperature a range of unusual properties, collectively known as 'pseudogap phenomena', are observed. Here we argue that a key pseudogap phenomenon-fluctuating superconductivity occurring substantially above the transition temperature-could be induced by the proximity of a Mott-insulating state. The Mott-insulating state in the kappa-(BEDT-TTF)2X organic molecular metals can be tuned, without doping, through superconductivity into a normal metallic state as a function of the parameter t/U, where t is the tight-binding transfer integral characterizing the metallic bandwidth and U is the on-site Coulomb repulsion. By exploiting a particularly sensitive probe of superconducting fluctuations, the vortex-Nernst effect, we find that a fluctuating regime develops as t/U decreases and the role of Coulomb correlations increases.
Collapse
Affiliation(s)
- Moon-Sun Nam
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK
| | | | | | | |
Collapse
|
4
|
Slighter CP, Coreyf RL, Curro NJ, Desoto SM, O'hara K, Imai T, Kini AM, Wang HH, Geiser U, Williams JM, Yoshimura K, Katoh M, Kosuge K. Nuclear magnetic resonance and electron spins: Some history, ancient and in the making. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01418639608240356] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Charles P. Slighter
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
| | - R. L. Coreyf
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
- d South Dakota School of Mines and Technology, Department of Physics , Rapid City , South Dakota , USA
| | - N. J. Curro
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
| | - S. M. Desoto
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
| | - K. O'hara
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
| | - T. Imai
- a Department of Physics and Materials Research Laboratory , University of Illinois , Urbana-Champaign, 1110 W Green Street, Urbana , Illinois , 61801-3080 , USA
- e Physics Department , Massachusetts Institute of Technology , Building 13, Room, Cambridge , Massachusetts , 3149 , USA
| | - A. M. Kini
- b Chemistry and Materials Science Division, Argonne National Laboratory , Argonne , Illinois , 60439 , USA
| | - H. H. Wang
- b Chemistry and Materials Science Division, Argonne National Laboratory , Argonne , Illinois , 60439 , USA
| | - U. Geiser
- b Chemistry and Materials Science Division, Argonne National Laboratory , Argonne , Illinois , 60439 , USA
| | - J. M. Williams
- b Chemistry and Materials Science Division, Argonne National Laboratory , Argonne , Illinois , 60439 , USA
| | - K. Yoshimura
- c Department of Chemistry, Faculty of Science , Kyoto University , Kyoto , 606 , Japan
| | - M. Katoh
- c Department of Chemistry, Faculty of Science , Kyoto University , Kyoto , 606 , Japan
| | - K. Kosuge
- c Department of Chemistry, Faculty of Science , Kyoto University , Kyoto , 606 , Japan
| |
Collapse
|
9
|
Vulcanescu V, Janossy B, Batail P, Fruchter L. Magnetization and Hc2 of a kappa -(BEDT-TTF)2Cu. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:2590-2593. [PMID: 9983765 DOI: 10.1103/physrevb.53.2590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
13
|
Dressel M, Klein O, Grüner G, Carlson KD, Wang HH, Williams JM. Electrodynamics of the organic superconductorsinebreak kappa -(BEDT-TTF)2Cu(NCS)2 and kappa -(BEDT-TTF)2Cu. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:13603-13615. [PMID: 9975555 DOI: 10.1103/physrevb.50.13603] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
15
|
Harshman DR, Fiory AT, Haddon RC, Kaplan ML, Pfiz T, Koster E, Shinkoda I, Williams DL. Magnetic penetration depth and fluxon-line dynamics in the organic superconductor kappa -. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:12990-12997. [PMID: 10010211 DOI: 10.1103/physrevb.49.12990] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
16
|
Prost D, Lenoir C, Batail P, Campbell IA, Fruchter L. Flux creep and scaling of the critical current with field in the quantum regime for a kappa -(BEDT-TTF)2Cu(NCN)2Br single crystal. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:4023-4026. [PMID: 10011299 DOI: 10.1103/physrevb.49.4023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
17
|
Dressel M, Bruder S, Grüner G, Carlson KD, Wang HH, Williams JM. Low-temperature microwave surface impedance of the conventional organic superconductor kappa -(BEDT-TTF)2Cu(NCS)2. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:9906-9909. [PMID: 10007256 DOI: 10.1103/physrevb.48.9906] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|