Carrier and epitaxial strain control of superconductivity in LaO thin film*

We report effects of carrier density and epitaxial strain on superconductivity in rock-salt lanthanum monoxide (LaO) epitaxial thin film [1]. Electron carrier doping via introducing oxygen vacancies resulted in a dome-shaped T_c as a function of carrier density. In addition, epitaxial strain influenced significantly the T_c despite its highly symmetric rock-salt structure. T_c was raised up to 5.2 K in tensilely strained thin film on LaAlO₃ substrate, in contrast with T_c of at most 4.5 K in compressive strained film on YAlO₃ substrate. [1] K. Kaminaga et al., J. Am. Chem. Soc. 140, 6754 (2018).