Spin-dependent transport through edge states in 2D semi-Dirac materials with Rashba spin-orbit coupling and band inversion

TL;DR

This paper explores how spin-orbit coupling affects edge states in 2D semi-Dirac materials, revealing spin-dependent edge channels and conductance oscillations that could enable spintronic applications.

Contribution

It introduces a topological invariant based on the Zak phase for semi-Dirac materials and analyzes the emergence of spin-dependent edge states influenced by Rashba spin-orbit coupling.

Findings

Edge states are topologically protected at specific momenta.

Spin-dependent edge states are localized based on spin and particle-hole character.

Conductance oscillations are robust and tunable due to spin precession.

Abstract

We investigate the bulk-boundary correspondence in two-dimensional type-I semi-Dirac materials with band inversion and Rashba spin-orbit coupling. Employing a dimensional reduction framework, we identify the Zak phase along the quadratically dispersing direction as a topological invariant that captures the presence of edge states. In the non-trivial topological regime, systems with finite width exhibit energy-dependent edge states that are topologically protected only at specific momenta. At kx equal to zero, symmetry-protected edge states emerge, analogous to the Rashba-free case. At finite kx, the interplay of spin-orbit coupling and band structure gives rise to spin-dependent edge states, localized on specific edges based on its spin and particle-hole character. We compute spin-resolved conductance through these edge channels and observe robust, tunable oscillations attributable to spin precession induced by the effective Rashba magnetic field. These results reveal how spin-orbit interactions enrich the edge physics of semi-Dirac systems and provide a platform for spintronic control in anisotropic topological materials.