Spatially dispersing Yu-Shiba-Rusinov states in the unconventional superconductor FeTe0.55Se0.45

被引：29

作者：

Chatzopoulos, Damianos ^{[1
]}

Cho, Doohee ^{[1
,2
]}

Bastiaans, Koen M. ^{[1
]}

Steffensen, Gorm O. ^{[3
]}

Bouwmeester, Damian ^{[1
,4
]}

Akbari, Alireza ^{[5
,6
,7
]}

Gu, Genda ^{[8
]}

Paaske, Jens ^{[3
]}

Andersen, Brian M. ^{[3
]}

Allan, Milan P. ^{[1
]}

机构：

[1] Leiden Univ, Leiden Inst Phys, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands

[2] Yonsei Univ, Dept Phys, Seoul 03722, South Korea

[3] Univ Copenhagen, Ctr Quantum Devices, Niels Bohr Inst, Univ Parken 5, DK-2100 Copenhagen O, Denmark

[4] Delft Univ Technol, Kavli Inst Nanosci, Lorentzweg 1, NL-2628 CJ Delft, Netherlands

[5] Max Planck Inst Chem Phys Solids, D-01187 Dresden, Germany

[6] POSTECH, Max Planck POSTECH Ctr Complex Phase Mat, Pohang 790784, Gyeongbuk, South Korea

[7] POSTECH, Dept Phys, Pohang 790784, Gyeongbuk, South Korea

[8] Brookhaven Natl Lab, Condensed Matter Phys & Mat Sci Dept, Upton, NY 11973 USA

来源：

NATURE COMMUNICATIONS | 2021年 / 12卷 / 01期

基金：

新加坡国家研究基金会; 欧洲研究理事会;

关键词：

IMPURITY STATES; FERMIONS; VISUALIZATION; FLUCTUATIONS; CONDUCTANCE;

D O I：

10.1038/s41467-020-20529-x

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：

By using scanning tunneling microscopy (STM) we find and characterize dispersive, energy-symmetric in-gap states in the iron-based superconductor FeTe0.55Se0.45, a material that exhibits signatures of topological superconductivity, and Majorana bound states at vortex cores or at impurity locations. We use a superconducting STM tip for enhanced energy resolution, which enables us to show that impurity states can be tuned through the Fermi level with varying tip-sample distance. We find that the impurity state is of the Yu-Shiba-Rusinov (YSR) type, and argue that the energy shift is caused by the low superfluid density in FeTe0.55Se0.45, which allows the electric field of the tip to slightly penetrate the sample. We model the newly introduced tip-gating scenario within the single-impurity Anderson model and find good agreement to the experimental data.

引用

页数：8

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