Monolayer Superconductivity and Tunable Topological Electronic Structure at the Fe(Te,Se)/Bi2Te3 Interface

Robert G. Moore, Qiangsheng Lu, Hoyeon Jeon, Xiong Yao, Tyler Smith, Yun Yi Pai, Michael Chilcote, Hu Miao, Satoshi Okamoto, An Ping Li, Seongshik Oh, Matthew Brahlek

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. While signatures of MBS have been observed in the magnetic vortex cores of bulk FeTe0.55Se0.45, inhomogeneity and disorder from doping make these signatures unclear and inconsistent between vortices. Here superconductivity is reported in monolayer (ML) FeTe1–ySey (Fe(Te,Se)) grown on Bi2Te3 by molecular beam epitaxy (MBE). Spin and angle-resolved photoemission spectroscopy (SARPES) directly resolve the interfacial spin and electronic structure of Fe(Te,Se)/Bi2Te3 heterostructures. For y = 0.25, the Fe(Te,Se) electronic structure is found to overlap with the Bi2Te3 TIS and the desired spin-momentum locking is not observed. In contrast, for y = 0.1, reduced inhomogeneity measured by scanning tunneling microscopy (STM) and a smaller Fe(Te,Se) Fermi surface with clear spin-momentum locking in the topological states are found. Hence, it is demonstrated that the Fe(Te,Se)/Bi2Te3 system is a highly tunable platform for realizing MBS where reduced doping can improve characteristics important for Majorana interrogation and potential applications.

Original languageEnglish (US)
Article number2210940
JournalAdvanced Materials
Volume35
Issue number22
DOIs
StatePublished - Jun 1 2023

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • molecular beam epitaxy
  • monolayer superconductivity
  • scanning tunneling microscopy
  • spin and angle resolved photoemission spectroscopy
  • superconductor
  • thin film heterostructure
  • topological superconductor

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