Tunable metal-insulator transition in LaTiO₃/CaVO₃ superlattices: A theoretical study

As one of intriguing physical results of electronic reconstruction, the metal-insulator transition plays an important role in exploring new electronic devices. In this study, the density functional theory is employed to investigate the metal-insulator transition in (LaTiO₃)_m/(CaVO₃)_n superlattices. Herein, three kinds of physical avenues, i.e., stacking orientation, epitaxial strain, and thickness periods, are used to tune the metal-insulator transition. Our calculations find that the 001-and 110-oriented (LaTiO₃)₁/(CaVO₃)₁ superlattices on SrTiO₃ substrate are insulating, while 111-oriented case is metallic. Such metallic behavior in 111 orientation can also be modulated by epitaxial strain. Besides the structural orientation and strain effect, the highly probable metal-insulator transition is presented in (LaTiO₃)_m/(CaVO₃)_n superlattices with increasing thickness. In addition, several interesting physical phenomena have also been revealed, such as selective charge transfer, charge ordering, and orbital ordering.