Strain tuned electronic and magnetic anisotropy in SrTiO3 (110) surface

Abstract

In this work, the density functional theory (DFT) calculations are employed to investigate the effect of in-plane strain on the electronic and magnetic anisotropy of SrTiO-terminated SrTiO3 (110) surface. The two-dimensional electron gas (2DEG) at the surface comes from the surface Ti 3d orbitals and exhibits anisotropic transport properties. The ordering of the lowest conduction band states can be tuned by in-plane strain. In addition, the in-plane strain can effectively modify and reduce the electron effective mass of the SrTiO3 (110) surface, and the effect of the in-plane strain on the two directions of [001] and [11¯0] is different. The magnetic moment of the unstrained surface Ti atom is 0.342 μB. The magnetic moment increases monotonically with the increasing of in-plane tensile strain and decreases quickly with increasing of the in-plane compressive strain. Importantly, the in-plane strain can change the magnetic moment of the system as well as its magnetic anisotropy energy and direction of easy magnetization axis. In-plane tensile strain causes a switch of the magnetic easy axis between parallel and perpendicular to the STO (110) surface.