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Title: Quasi-2D superconductivity in FeTe0.55Se0.45 ultrathin film [Quasi Two-Dimensional Superconductivity in FeTe0.55Se0.45 ultrathin film]

Abstract

Iron-chalcogenide FeTe0.55Se0.45 was found to be a promising topological superconducting candidate recently, which may host Majorana bound state in the vortex core and thus attracts intensive research interests in this material. In this report, mechanically exfoliated FeTe0.55Se0.45 superconducting thin films close to the two-dimensional (2D) limit, i.e. sample thickness is on the order of coherence length, were studied systematically by means of electrical transport and point-contact Andreev-reflection spectroscopy (PCARS) measurements. The quasi-2D nature of FeTe0.55Se0.45 thin films is evidenced by the observation of Berezinskii–Kosterlitz–Thouless (BKT) transition and anisotropic upper critical fields in the vicinity of superconducting transition. Compared to bulk samples, we found that the superconducting transition temperature is only slightly suppressed even for films down to 5 nm. The superconducting gap symmetry remains unchanged and the gap size is weakly affected by tailoring thickness. Furthermore, our findings suggest that the superconductivity of FeTe0.55Se0.45 thin films is rather robust against reduced dimensions. It provides a novel platform for device applications for quantum computations in combination with possible realization of Majorana modes in this material.

Authors:
ORCiD logo [1];  [2];  [2];  [2]; ORCiD logo [3];  [4];  [5];  [6]
  1. Renmin Univ. of China, Beijing (People's Republic of China); Southern Univ. of Science and Technology, Shenzhen (People's Republic of China)
  2. Southern Univ. of Science and Technology, Shenzhen (People's Republic of China)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Renmin Univ. of China, Beijing (People's Republic of China)
  5. Chongqing Univ., Chongqing (People's Republic of China)
  6. Southern Univ. of Science and Technology, Shenzhen (People's Republic of China); Chongqing Univ., Chongqing (People's Republic of China)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1525398
Report Number(s):
BNL-211753-2019-JAAM
Journal ID: ISSN 0953-8984
Grant/Contract Number:  
SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 31; Journal Issue: 26; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 2D superconductivity; FeTe0.55Se0.45 thin film; BKT transition; point-contact Andreev-reflection spectroscopy

Citation Formats

Tang, Fangdong, Wang, Peipei, Wang, Peng, Gan, Yuan, Gu, Genda D., Zhang, Wei, He, Mingquan, and Zhang, Liyuan. Quasi-2D superconductivity in FeTe0.55Se0.45 ultrathin film [Quasi Two-Dimensional Superconductivity in FeTe0.55Se0.45 ultrathin film]. United States: N. p., 2019. Web. doi:10.1088/1361-648X/ab14c3.
Tang, Fangdong, Wang, Peipei, Wang, Peng, Gan, Yuan, Gu, Genda D., Zhang, Wei, He, Mingquan, & Zhang, Liyuan. Quasi-2D superconductivity in FeTe0.55Se0.45 ultrathin film [Quasi Two-Dimensional Superconductivity in FeTe0.55Se0.45 ultrathin film]. United States. https://doi.org/10.1088/1361-648X/ab14c3
Tang, Fangdong, Wang, Peipei, Wang, Peng, Gan, Yuan, Gu, Genda D., Zhang, Wei, He, Mingquan, and Zhang, Liyuan. Tue . "Quasi-2D superconductivity in FeTe0.55Se0.45 ultrathin film [Quasi Two-Dimensional Superconductivity in FeTe0.55Se0.45 ultrathin film]". United States. https://doi.org/10.1088/1361-648X/ab14c3. https://www.osti.gov/servlets/purl/1525398.
@article{osti_1525398,
title = {Quasi-2D superconductivity in FeTe0.55Se0.45 ultrathin film [Quasi Two-Dimensional Superconductivity in FeTe0.55Se0.45 ultrathin film]},
author = {Tang, Fangdong and Wang, Peipei and Wang, Peng and Gan, Yuan and Gu, Genda D. and Zhang, Wei and He, Mingquan and Zhang, Liyuan},
abstractNote = {Iron-chalcogenide FeTe0.55Se0.45 was found to be a promising topological superconducting candidate recently, which may host Majorana bound state in the vortex core and thus attracts intensive research interests in this material. In this report, mechanically exfoliated FeTe0.55Se0.45 superconducting thin films close to the two-dimensional (2D) limit, i.e. sample thickness is on the order of coherence length, were studied systematically by means of electrical transport and point-contact Andreev-reflection spectroscopy (PCARS) measurements. The quasi-2D nature of FeTe0.55Se0.45 thin films is evidenced by the observation of Berezinskii–Kosterlitz–Thouless (BKT) transition and anisotropic upper critical fields in the vicinity of superconducting transition. Compared to bulk samples, we found that the superconducting transition temperature is only slightly suppressed even for films down to 5 nm. The superconducting gap symmetry remains unchanged and the gap size is weakly affected by tailoring thickness. Furthermore, our findings suggest that the superconductivity of FeTe0.55Se0.45 thin films is rather robust against reduced dimensions. It provides a novel platform for device applications for quantum computations in combination with possible realization of Majorana modes in this material.},
doi = {10.1088/1361-648X/ab14c3},
journal = {Journal of Physics. Condensed Matter},
number = 26,
volume = 31,
place = {United States},
year = {Tue Apr 23 00:00:00 EDT 2019},
month = {Tue Apr 23 00:00:00 EDT 2019}
}

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