Observation of strong electron pairing on bands without Fermi surfaces in LiFe1-xCoxAs

被引：71

作者：

Miao, H. ^{[1
]}

Qian, T. ^{[1
]}

Shi, X. ^{[1
]}

Richard, P. ^{[1
,2
]}

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

Hoesch, M. ^{[3
]}

Xing, L. Y. ^{[1
]}

Wang, X. -C. ^{[1
]}

Jin, C. -Q. ^{[1
,2
]}

Hu, J. -P. ^{[1
,2
,4
]}

Ding, H. ^{[1
,2
]}

机构：

[1] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China

[2] Collaborat Innovat Ctr Quantum Matter, Beijing 100190, Peoples R China

[3] Diamond Light Source, Didcot OX11 0DE, Oxon, England

[4] Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA

来源：

NATURE COMMUNICATIONS | 2015年 / 6卷

关键词：

SUPERCONDUCTIVITY; GAPS;

D O I：

10.1038/ncomms7056

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

In conventional BCS superconductors, the quantum condensation of superconducting electron pairs is understood as a Fermi surface instability, in which the low-energy electrons are paired by attractive interactions. Whether this explanation is still valid in high-T-c superconductors such as cuprates and iron-based superconductors remains an open question. In particular, a fundamentally different picture of the electron pairs, which are believed to be formed locally by repulsive interactions, may prevail. Here we report a high-resolution angle-resolved photoemission spectroscopy study on LiFe1-xCoxAs. We reveal a large and robust superconducting gap on a band sinking below the Fermi level on Co substitution. The observed Fermi-surface-free superconducting order is also the largest over the momentum space, which rules out a proximity effect origin and indicates that the order parameter is not tied to the Fermi surface as a result of a surface instability.

引用

页数：6

共 35 条

[1] Superconductivity from repulsion in LiFeAs: Novel s-wave symmetry and potential time-reversal symmetry breaking [J].

Ahn, F. ;

Eremin, I. ;

Knolle, J. ;

Zabolotnyy, V. B. ;

Borisenko, S. V. ;

Buechner, B. ;

Chubukov, A. V. .

PHYSICAL REVIEW B, 2014, 89 (14)

[2] Anisotropic Energy Gaps of Iron-Based Superconductivity from Intraband Quasiparticle Interference in LiFeAs [J].

Allan, M. P. ;

Rost, A. W. ;

Mackenzie, A. P. ;

Xie, Yang ;

Davis, J. C. ;

Kihou, K. ;

Lee, C. H. ;

Iyo, A. ;

Eisaki, H. ;

Chuang, T. -M. .

SCIENCE, 2012, 336 (6081) :563-567

[3] Do Transition-Metal Substitutions Dope Carriers in Iron-Based Superconductors? [J].

Berlijn, Tom ;

Lin, Chia-Hui ;

Garber, William ;

Ku, Wei .

PHYSICAL REVIEW LETTERS, 2012, 108 (20)

[4] One-Sign Order Parameter in Iron Based Superconductor [J].

Borisenko, Sergey V. ;

Zabolotnyy, Volodymyr B. ;

Kordyuk, Alexnader A. ;

Evtushinsky, Danil V. ;

Kim, Timur K. ;

Morozov, Igor V. ;

Follath, Rolf ;

Buechner, Bernd .

SYMMETRY-BASEL, 2012, 4 (01) :251-264

[5] BCS-BEC crossover: From high temperature superconductors to ultracold superfluids [J].

Chen, QJ ;

Stajic, J ;

Tan, S ;

Levin, K .

PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS, 2005, 412 (01) :1-88

[6] Concepts relating magnetic interactions, intertwined electronic orders, and strongly correlated superconductivity [J].

Davis, J. C. Seamus ;

Lee, Dung-Hai .

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2013, 110 (44) :17623-17630

[7] Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2 [J].

Ding, H. ;

Richard, P. ;

Nakayama, K. ;

Sugawara, K. ;

Arakane, T. ;

Sekiba, Y. ;

Takayama, A. ;

Souma, S. ;

Sato, T. ;

Takahashi, T. ;

Wang, Z. ;

Dai, X. ;

Fang, Z. ;

Chen, G. F. ;

Luo, J. L. ;

Wang, N. L. .

EPL, 2008, 83 (04)

[8] Band-edge BCS-BEC crossover in a two-band superconductor: physical properties and detection parameters [J].

Guidini, Andrea ;

Perali, Andrea .

SUPERCONDUCTOR SCIENCE & TECHNOLOGY, 2014, 27 (12)

[9] Gap symmetry and structure of Fe-based superconductors [J].

Hirschfeld, P. J. ;

Korshunov, M. M. ;

Mazin, I. I. .

REPORTS ON PROGRESS IN PHYSICS, 2011, 74 (12)

[10] Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors [J].

Hu, Jiangping ;

Ding, Hong .

SCIENTIFIC REPORTS, 2012, 2

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