Electron States Emerging at Magnetic Domain Wall of magnetic semiconductors with strong Rashba effect

TL;DR

This paper investigates electron states at magnetic domain walls in semiconductors with strong Rashba effects, revealing bound and resonant states influenced by magnetization and spin-orbit coupling, with potential for chiral conducting channels.

Contribution

It introduces a comprehensive model and numerical analysis of electron states at various magnetic domain walls in Rashba semiconductors, predicting novel bound and resonant states.

Findings

Domain walls host bound electron states.

Domain walls induce one-dimensional resonant states.

Surface states are sensitive to magnetization orientation.

Abstract

In the present article, we explore the electron properties of magnetic semiconductors with strong Rashba spin-orbit coupling taking into account the presence of domain walls at the sample surface. We consider antiphase domain walls separating domains with both in-plane and out-of-plane magnetization as well as noncollinear domain walls. First, we propose the model and unveil general physical picture of phenomenon supported by analytical arguments. Further, we perform a comprehensive tight-binding numerical calculations to provide a profound understanding of our findings. A domain wall separating domains with any polarization directions is demonstrated to host a bound state. What is more interesting is that we predict that either of these domain walls also induces one-dimensional resonant state. The surface energy spectrum and spin polarization of the states are highly sensitive to the magnetization orientation in the adjacent domains. The spectral broadening and the spatial localization of the resonant state depend significantly on a relation between the Rashba splitting and the exchange one. Our estimation shows that chiral conducting channels associated with the long-lived resonant states can emerge along the magnetic domain walls and can be accessed experimentally at the surface of BiTeI doped with transition metal atoms.