Metal–insulator transitions in dimensionality controlled LaxSr1−xVO3 films

Carrier doping into two dimensional (2D) Mott insulators is one of the prospective strategies for exploring exotic quantum phenomena. Although ultra-thin oxide films are one such target, it is vitally important to fabricate well-defined and clean samples to extract intrinsic properties. In this study, we start from establishing the growth of clean SrVO3 films with a low residual resistivity (∼4 × 10−7 Ω cm) and a high mobility (∼103 cm2/V s). By confining them with SrTiO3 barrier layers, the Mott insulator state appears at the thickness below 3 unit cells (u.c.). By the electron doping in the form of LaxSr1−xVO3 for such two dimensional systems (2 and 3 u.c), metallic-like phases appear in a narrow x region around x = 0.17, indicating a collapse of the Mott insulator state. This study demonstrates that artificial 2D systems of clean oxides are a promising playground for exploring novel Mott physics in confined systems.