Spin Transfer Torque in the Semiconductor/Ferromagnetic Structure in the Presence of Rashba Effect

TL;DR

This paper investigates how the Rashba effect influences spin transfer torque in semiconductor/ferromagnetic structures, revealing that it enhances the torque components and affects electron transmission probabilities.

Contribution

It introduces a detailed analysis of Rashba effect impacts on spin transfer torque using two models, highlighting additional contributions and effects on transverse components.

Findings

Rashba effect increases the difference between Fermi surfaces.

Rashba effect adds an extra contribution to spin transfer torque.

Transmission probability decreases with larger Fermi surface differences.

Abstract

Spin transfer torque in magnetic structures occurs when the transverse component of the spin current that flows from the nonmagnetic medium to ferromagnetic medium are absorbed by the interface. In this paper, considering the Rashba effect on semiconductor region, we have discussed the spin transfer torque in semiconductor/ferromagnetic structure and obtained the components of spin-current density for two models: (I)-single electron and (II)- the distribution of electrons. We have shown that whatever the difference between Fermi surfaces in semiconductor and Fermi spheres for the up and down spins in ferromagnetic increase, the transmission probability decreases. The obtained results for the values used in this article illustrate that Rashba effect increases the difference between a Fermi sphere in semiconductors and Fermi sphere for the up and down spins in ferromagnetic. The results also show that the Rashba effect, brings an additional contribution to the components of spin transfer torque, which is not exist in the absence of the Rashba interaction. Moreover, the Rashba term has also different effects on the transverse components of the spin torque transfer.