Weak Superconducting Pairing and a Single Isotropic Energy Gap in Stoichiometric LiFeAs

被引：71

作者：

Inosov, D. S. ^{[1
]}

White, J. S. ^{[2
]}

Evtushinsky, D. V. ^{[3
]}

Morozov, I. V. ^{[3
,4
]}

Cameron, A. ^{[5
]}

Stockert, U. ^{[3
]}

Zabolotnyy, V. B. ^{[3
]}

Kim, T. K. ^{[3
]}

Kordyuk, A. A. ^{[3
,6
]}

Borisenko, S. V. ^{[3
]}

Forgan, E. M. ^{[5
]}

Klingeler, R. ^{[3
]}

Park, J. T. ^{[1
]}

Wurmehl, S. ^{[3
]}

Vasiliev, A. N. ^{[4
]}

Behr, G. ^{[3
]}

Dewhurst, C. D. ^{[7
]}

Hinkov, V. ^{[1
]}

机构：

[1] Max Planck Inst Solid State Res, D-70569 Stuttgart, Germany

[2] Paul Scherrer Inst, Neutron Scattering Lab, CH-5232 Villigen, Switzerland

[3] IFW Dresden, Leibnitz Inst Solid State Res, D-01171 Dresden, Germany

[4] Moscow MV Lomonosov State Univ, Moscow 119991, Russia

[5] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England

[6] Natl Acad Sci Ukraine, Inst Met Phys, UA-03142 Kiev, Ukraine

[7] Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France

来源：

PHYSICAL REVIEW LETTERS | 2010年 / 104卷 / 18期

基金：

英国工程与自然科学研究理事会;

关键词：

MAGNETIC-FIELD; VORTEX CORE;

D O I：

10.1103/PhysRevLett.104.187001

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report superconducting (SC) properties of stoichiometric LiFeAs (T-c = 17 K) studied by small-angle neutron scattering (SANS) and angle-resolved photoemission (ARPES). Although the vortex lattice exhibits no long-range order, well-defined SANS rocking curves indicate better ordering than in chemically doped 122 compounds. The London penetration depth lambda(ab)(0) = 210 +/- 20 nm, determined from the magnetic field dependence of the form factor, is compared to that calculated from the ARPES band structure with no adjustable parameters. The temperature dependence of lambda(ab) is best described by a single isotropic SC gap Delta(0) = 3.0 +/- 0.2 meV, which agrees with the ARPES value of Delta(ARPES)(0) = 3.1 +/- 0.3 meV and corresponds to the ratio 2 Delta/k(B)T(c) = 4.1 +/- 0.3, approaching the weak-coupling limit predicted by the BCS theory. This classifies LiFeAs as a weakly coupled single-gap superconductor.

引用

页数：4

共 40 条

[1] THEORY OF SUPERCONDUCTIVITY [J].

BARDEEN, J ;

COOPER, LN ;

SCHRIEFFER, JR .

PHYSICAL REVIEW, 1957, 108 (05) :1175-1204

[2] Coherence length in superconductors from weak to strong coupling [J].

Benfatto, L ;

Toschi, A ;

Caprara, S ;

Castellani, C .

PHYSICAL REVIEW B, 2002, 66 (05) :1-12

[3]

BORISENKO SV, ARXIV10011147

[4]

CHANDRASEKHAR BS, 1993, ANN PHYS-LEIPZIG, V2, P535, DOI 10.1002/andp.19935050604

[5] STUDY OF INTERMEDIATE MIXED STATE OF NIOBIUM BY SMALL-ANGLE NEUTRON-SCATTERING [J].

CHRISTEN, DK ;

TASSET, F ;

SPOONER, S ;

MOOK, HA .

PHYSICAL REVIEW B, 1977, 15 (09) :4506-4509

[6] SIMPLE MODEL FOR VORTEX CORE IN A TYPE-II SUPERCONDUCTOR [J].

CLEM, JR .

JOURNAL OF LOW TEMPERATURE PHYSICS, 1975, 18 (5-6) :427-435

[7] DIRECT MEASUREMENT OF QUASIPARTICLE-LIFETIME BROADENING IN A STRONG-COUPLED SUPERCONDUCTOR [J].

DYNES, RC ;

NARAYANAMURTI, V ;

GARNO, JP .

PHYSICAL REVIEW LETTERS, 1978, 41 (21) :1509-1512

[8] Vortices in superconducting Ba(Fe0.93Co0.07)2As2 studied via small-angle neutron scattering and Bitter decoration [J].

Eskildsen, M. R. ;

Vinnikov, L. Ya. ;

Blasius, T. D. ;

Veshchunov, I. S. ;

Artemova, T. M. ;

Densmore, J. M. ;

Dewhurst, C. D. ;

Ni, N. ;

Kreyssig, A. ;

Bud'ko, S. L. ;

Canfield, P. C. ;

Goldman, A. I. .

PHYSICAL REVIEW B, 2009, 79 (10)

[9] Momentum-resolved superconducting gap in the bulk of Ba1-xKxFe2As2 from combined ARPES and μSR measurements [J].

Evtushinsky, D. V. ;

Inosov, D. S. ;

Zabolotnyy, V. B. ;

Viazovska, M. S. ;

Khasanov, R. ;

Amato, A. ;

Klauss, H-H ;

Luetkens, H. ;

Niedermayer, Ch ;

Sun, G. L. ;

Hinkov, V. ;

Lin, C. T. ;

Varykhalov, A. ;

Koitzsch, A. ;

Knupfer, M. ;

Buechner, B. ;

Kordyuk, A. A. ;

Borisenko, S. V. .

NEW JOURNAL OF PHYSICS, 2009, 11

[10] Momentum dependence of the superconducting gap in Ba1-xKxFe2As2 [J].