Comments on "Spin-dependent tunneling through a symmetric semiconductor barrier: The Dresselhaus effect"

TL;DR

This paper critiques a previous study on spin-dependent tunneling, arguing that their treatment of the Dresselhaus term in contacts is incorrect and discussing issues related to spin polarization definitions.

Contribution

It provides a correction to the treatment of the Dresselhaus term in contacts and discusses the validity of spin polarization measures in spin-orbit coupled systems.

Findings

The previous treatment does not satisfy the Schrödinger equation.

The full current operator significantly affects spin polarization.

Questions the appropriateness of current spin polarization definitions.

Abstract

In a recent paper [Phys. Rev. B 72, 153314 (2005)], the $k^{3}$-Dresselhaus term in the contacts and the full form of the current operator are considered for spin-dependent tunneling through a symmetric barrier. The authors found that the full form of the current operator has a much larger influence on the spin polarization than it was initially thought. In this Comment we will show that their treatment of the other problem, the $k^{3}$-Dresselhaus term in the contacts, is incorrect. Their proposed solution in the contacts simply does not obey the Schr\"{o}dinger equation. In this context we also comment on the definition and the suitability of spin polarization in contacts with spin-orbit coupling.