Momentum dependence of the superconducting gap in Ba1-xKxFe2As2

被引：181

作者：

Evtushinsky, D. V. ^{[1
]}

Inosov, D. S. ^{[2
]}

Zabolotnyy, V. B. ^{[1
]}

Koitzsch, A. ^{[1
]}

Knupfer, M. ^{[1
]}

Buechner, B. ^{[1
]}

Viazovska, M. S. ^{[3
]}

Sun, G. L. ^{[2
]}

Hinkov, V. ^{[2
]}

Boris, A. V. ^{[2
,4
]}

Lin, C. T. ^{[2
]}

Keimer, B. ^{[2
]}

Varykhalov, A. ^{[5
]}

Kordyuk, A. A. ^{[1
,6
]}

Borisenko, S. V. ^{[1
]}

机构：

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

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

[3] Max Planck Inst Math, D-53111 Bonn, Germany

[4] Univ Loughborough, Dept Phys, Loughborough LE11 3TU, Leics, England

[5] BESSY, D-12489 Berlin, Germany

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

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 05期

关键词：

barium compounds; high-temperature superconductors; iron compounds; photoelectron spectra; potassium compounds; quasiparticles; superconducting energy gap;

D O I：

10.1103/PhysRevB.79.054517

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The precise momentum dependence of the superconducting gap in the iron-arsenide superconductor Ba1-xKxFe2As2 (BKFA) with T-c=32 K was determined from angle-resolved photoemission spectroscopy (ARPES) via fitting the distribution of the quasiparticle density to a model. The model incorporates finite lifetime and experimental resolution effects, as well as accounts for peculiarities of BKFA electronic structure. We have found that the value of the superconducting gap is practically the same for the inner Gamma barrel, X pocket, and "blade" pocket, and equals 9 meV, while the gap on the outer Gamma barrel is estimated to be less than 4 meV, resulting in 2 Delta/k(B)T(c)=6.8 for the large gap and 2 Delta/k(B)T(c)< 3 for the small gap. A large (77 +/- 3 %) nonsuperconducting component in the photoemission signal is observed below T-c. Details of gap extraction from ARPES data are discussed in Appendixes A x B.

引用

页数：13

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