Higher-order epitaxy: A pathway to suppressing structural instability and emergent superconductivity

ORAL

Abstract

Molecular beam epitaxy enables the growth of thin film materials with novel properties and functionalities. Typically, the lattice constants of films and substrates are designed to match to minimise disorders and strains. However, significant lattice mismatches can result in higher-order epitaxy, where commensurate growth occurs with a period defined by integer multiples of the lattice constants. Despite its potential, higher-order epitaxy is rarely used to enhance material properties or induce emergent phenomena. Here, we report single-crystalline FeTe films grown via 6:5 commensurate higher-order epitaxy on CdTe(001) substrates. Scanning transmission electron microscopy reveals self-organised periodic interstitials near the interface, arising from higher-order lattice matching. Synchrotron x-ray diffraction shows that the tetragonal-to-monoclinic structural transition in bulk FeTe is strongly suppressed. Remarkably, these films exhibit substrate-selective two-dimensional superconductivity, likely due to suppressed monoclinic distortion. These findings demonstrate the potential of higher-order epitaxy as a tool to control materials and inducing emergent phenomena.

*This work was supported by JSPS KAKENHI (Grant Numbers 24K17020, 22K18965, 23H04017, 23H05431, 23H05462, 24H00417, 24H01652, and 25H02126.), JST FOREST (Grant Number JPMJFR2038), JST CREST (Grant Numbers JPMJCR1874 and JPMJCR23O3), Mitsubishi Foundation, Sumitomo Foundation, Tanaka Kikinzoku Memorial Foundation, and the RIKEN TRIP initiative (Many-body Electron Systems). This work was performed under the approval of the Photon Factory Program Advisory Committee (Proposal No. 2022G551).

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Publication: Y. Sato et al., arXiv:2510.07947

Presenters

  • Yuki Sato

    • RIKEN Center for Emergent Matter Science (CEMS)
    • RIKEN

Authors

  • Yuki Sato

    • RIKEN Center for Emergent Matter Science (CEMS)
    • RIKEN

  • Soma Nagahama

    • The University of Tokyo

  • Shunsuke Kitou

    • University of Tokyo
    • The University of Tokyo

  • Hajime Sagayama

    • KEK
    • High Energy Accelerator Research Organization

  • Ilya Belopolski

    • RIKEN, CEMS
    • RIKEN Center for Emergent Matter Science (CEMS)
    • RIKEN

  • Ryutaro Yoshimi

    • Department of Advanced Materials Science, The University of Tokyo
    • The University of Tokyo
    • RIKEN

  • Minoru Kawamura

    • RIKEN Center for Emergent Matter Science (CEMS)
    • RIKEN

  • Atsushi Tsukazaki

    • Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo
    • The University of Tokyo
    • University of Tokyo

  • Naoya Kanazawa

    • Institute of Industrial Science, University of Tokyo

  • Takuya Nomoto

    • Tokyo Metropolitan University

  • Ryotaro Arita

    • Univ of Tokyo
    • The University of Tokyo, RIKEN CEMS
    • University of Tokyo

  • Takahisa Arima

    • University of Tokyo
    • RIKEN

  • Masashi Kawasaki

    • Univ of Tokyo, RIKEN CEMS
    • University of Tokyo
    • RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo
    • The University of Tokyo, RIKEN

  • Yoshinori Tokura

    • The University of Tokyo
    • Univ of Tokyo
    • RIKEN Center for Emergent Matter Science (CEMS), Tokyo College, the University of Tokyo
    • The University of Tokyo, RIKEN
    • University of Tokyo