Stoichiometric effect on the physical properties of Sr₃SnO thin films fabricated by sputtering method

The antiperovskite oxides have attracted interest due to their topologically non-trivial band structures. Among them, Sr₃SnO has a crystallographic point group symmetry, leading to the prediction that it is a topological crystalline insulator (TCI) [1]. Sr_3-xSn_xO single crystals with a Sr-deficiency have been reported to exhibit superconductivity, and it has thus been suggested as a possible topological superconductor [2]. To advance the realization of topological electronics, thin film fabrication is necessary. To date, MBE growth has appeared successful in preparing the Sr₃SnO thin films, but their high chemical instability has limited extensive studies on this material [3].

Here, we present the fabrication of Sr₃SnO thin film using a sputtering method and investigate the physical properties depending on the stoichiometry. The Sr_3-xSn_xO compositional spread films were prepared by the co-sputtering of Sr and SnO₂. The Sr₃SnO phase was confirmed by ex-situ x-ray diffraction measurements, and the stoichiometric information was obtained from wavelength-dispersive spectroscopy measurements. The measurement of temperature-dependent resistivity of Sr_3-xSnO films was attempted using a home-built kit to prevent the degradation of the samples. We discuss the synthesis mechanism of the Sr₃SnO phase. This work would contribute to encouraging the research on antiperovskite oxides.



[1] Y. Ma et al., Adv. Mater. 32, 2000809 (2020)

[2] J. N. Hausmann et al., Supercond. Sci. Technol. 31, 055012 (2018)

[3] H. Nakamura et al., APL Mater. 10, 060904 (2022).