Theoretical studies of Rashba effect on a two-dimensional topological insulator and monolayer of 5d transition metal oxides 2DEG

Abstract

Interlocking between spin and the crystal momentum of electrons resulting from the spin-orbit coupling in two dimensional semiconductors was introduced in 1984 by Rashba and Bychkov, named as the Rashba effect. Since then, the field of Rashba effect has been greatly expanded to a vast number of materials beyond semiconductors. Recently, it shows the effective spin generation, manipulation and detection are possible via Rashba effect, relating its importance to spin Hall effect, spin galvanic effect, topological states and so on. Not only that, but a new concept of spin device utilizing the Rashba effect, Das Datta-type transistors, has been also realizing. In this talk, we briefly introduce the physics of Rashba, and two theoretical studies of the Rashba effect ongoing in our group: (i) a two-dimensional topological insulator, where the possibly flappable electric polarization allows us to effectively control spin textures. (ii)2DEG formed on 5d transition metal oxides monolayer sandwiched by ferroelectric materials in which the soft phonon modes coupled to the spin greatly enhances the Rashba effect. In the end, we will also talk about the future direction of the current studies.