Electron spin diffusion at the interface of multiferroic oxides

TL;DR

This paper investigates how spin diffusion occurs in a two-dimensional electron gas at the interface of oxide heterostructures influenced by multiferroic TbMnO$_3$, highlighting the roles of magnetic interactions and Coulomb scattering.

Contribution

It provides a detailed analysis of spin diffusion mechanisms at oxide interfaces, emphasizing the impact of spiral magnetic moments and Coulomb scattering on spin transport.

Findings

Spin diffusion length remains finite regardless of spin polarization direction.

Coulomb scattering significantly suppresses spin diffusion.

Magnetic interactions at the interface influence spin transport properties.

Abstract

We study the spin diffusion in a two-dimensional electron gas at the interface of oxide heterostructure LaAlO$_3$/SrTiO$_3$ grown on multiferroic TbMnO$_3$ at 15 K by means of the kinetic spin Bloch equation approach. The spiral magnetic moments of Mn$^{3+}$ in TbMnO$_3$ interact with the diffusing spins at the LaAlO$_3$/SrTiO$_3$ interface via the Heisenberg exchange interaction. It is demonstrated that the spin diffusion length is always finite, despite the polarization direction of the injected spins. Our study also reveals the important role played by the Coulomb scattering, which can effectively suppress the spin diffusion.