Hidden Ladder in SrMoO$_3$/SrTiO$_3$ Superlattices: Experiments and Theoretical Calculations

Hiroshi Takatsu; Naoya Yamashina; Masayuki Ochi; Hsin-Hui Huang; Shunsuke Kobayashi; Akihide Kuwabara; Takahito Terashima; Kazuhiko Kuroki; Hiroshi Kageyama

doi:10.7566/JPSJ.89.074801

paper

Hidden Ladder in SrMoO $_{3}$ /SrTiO $_{3}$ Superlattices: Experiments and Theoretical Calculations

arXiv:2012.02406 · doi:10.7566/JPSJ.89.074801

Abstract

A double-layered perovskite oxide Sr $_{3}$ Mo $_{2}$ O $_{7}$ is considered a "hidden ladder" system with wide and narrow bands near the Fermi level, for which high- $T_{c}$ superconductivity is expected. However, the difficulty in synthesis, especially in the preparation of samples without oxygen deficiency, can hinder the observation of superconductivity. In this study, we constructed a double-layer SrMoO $_{3}$ block through artificial superlattices with the insulating SrTiO $_{3}$ block, (SrMoO $_{3}$ ) $_{m}$ /(SrTiO $_{3}$ ) $_{t}$ ( $m = 2, 4$ ; $t = 4$ ). First-principles calculations for bilayered SrMoO $_{3}$ ( $m = 2$ ) exhibit a wide-narrow band structure near the Fermi level, which bears a close resemblance to Sr $_{3}$ Mo $_{2}$ O $_{7}$ . The dispersion along the $k_{z}$ direction is strongly suppressed by increasing the number of the SrTiO $_{3}$ layers, $t$ . However, no superconductivity is observed down to 0.1 K. We discuss the absence of the superconductivity for the present films on the basis of results of scanning transmission electron microscopy and band structure calculations.

arXiv comment7 pages, 6 figures, Supplemental Material

Hidden Ladder in SrMoO3​/SrTiO3​ Superlattices: Experiments and Theoretical Calculations

Abstract

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Hidden Ladder in SrMoO $_{3}$ /SrTiO $_{3}$ Superlattices: Experiments and Theoretical Calculations