Emergent magnetic and charge ordered phases in freestanding ultrathin LaVO₃

Original · EN

Transition metal oxide perovskites are an ideal platform for exploring the interplay between spin, orbital, charge and lattice degrees of freedom. Among them, LaVO₃ has been extensively studied in heterostructures and superlattices, where exotic phases have been reported. Motivated by the advances in freestanding oxide membranes, we investigate the intrinsic properties of freestanding ultrathin LaVO₃ films using density functional theory. Our calculations reveal a sequence of magnetic phase transitions with thickness, starting from stripe-AFM in monolayer until the bulk like C-AFM is recovered. Beyond four layers, polar catastrophe driven charge transfer dopes the surface layers giving rise to stripe-AFM and ferromagnetic surface states while the central layers remain bulk like. We further explore this fact by studying charge doped monolayer, discovering that hole doping drives the system into ferromagnetic state. Doping also induced charge ordering in the system. A striped charge ordering pattern is observed at 0.5 h/fu, while a 3:1 stripe pattern emerges at 0.25 h/fu, indicating that the periodicity of the superstructure changes with doping concentration.