Superconductivity in Single-Quintuple-Layer Bi2Te3 Grown on Epitaxial FeTe

Hailang Qin; Bin Guo; Linjing Wang; Meng Zhang; Bochao Xu; Kaige Shi; Tianluo Pan; Liang Zhou; Junshu Chen; Yang Qiu; Bin Xi; Iam Keong Sou; Dapeng Yu; Wei-Qiang Chen; Hongtao He; Fei Ye; Jia-Wei Mei; Gan Wang

doi:10.1021/acs.nanolett.9b05167

Superconductivity in Single-Quintuple-Layer Bi₂Te₃ Grown on Epitaxial FeTe

Nano Lett. 2020 May 13;20(5):3160-3168. doi: 10.1021/acs.nanolett.9b05167. Epub 2020 Mar 31.

Authors

Hailang Qin¹, Bin Guo¹, Linjing Wang¹, Meng Zhang¹, Bochao Xu¹, Kaige Shi¹, Tianluo Pan¹, Liang Zhou¹, Junshu Chen¹, Yang Qiu², Bin Xi³, Iam Keong Sou⁴, Dapeng Yu¹, Wei-Qiang Chen¹, Hongtao He¹, Fei Ye¹, Jia-Wei Mei¹, Gan Wang¹

Affiliations

¹ Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
² Materials Characterization and Preparation Center, Southern University of Science and Technology, Shenzhen 518055, China.
³ School of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China.
⁴ Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.

PMID: 32207627
DOI: 10.1021/acs.nanolett.9b05167

Abstract

How an interfacial superconductivity emerges during the nucleation and epitaxy is of great importance not only for unveiling the physical insights but also for finding a feasible way to tune the superconductivity via interfacial engineering. In this work, we report the nanoscale creation of a robust and relatively homogeneous interfacial superconductivity (T_C ≈ 13 K) on the epitaxial FeTe surface, by van der Waals epitaxy of single-quintuple-layer topological insulator Bi₂Te₃. Our study suggests that the superconductivity in the Bi₂Te₃/FeTe heterostructure is generated at the interface and that the superconductivity at the interface does not enhance or weaken with the increase of the Bi₂Te₃ thickness beyond 1 quintuple layer (QL). The observation of the topological surface states crossing Fermi energy in the Bi₂Te₃/FeTe heterostructure with the average Bi₂Te₃ thickness of about 20 QL provides further evidence that this heterostructure may potentially host Majorana zero modes.

Keywords: FeTe/Bi2Te3; charge transfer; interfacial superconductivity; scanning tunneling microscopy; step-flow epitaxy.