Magnetic field induced Fabry-P\'erot resonances in helical edge states

TL;DR

This paper demonstrates that magnetic field-induced Fabry-Pérot resonances in helical edge states can be tuned by changing the magnetic field direction, providing a novel method to probe their helical nature.

Contribution

It reveals that magnetic field direction controls Fabry-Pérot resonances in helical edge states, unlike in non-helical systems, offering a new way to investigate their properties.

Findings

Resonances are tunable by magnetic field direction.

Helical edge states exhibit unique magnetic field responses.

Resonances serve as probes for helical nature.

Abstract

We study electronic transport across a helical edge state exposed to a uniform magnetic ({$\vec B$}) field over a finite length. We show that this system exhibits Fabry-P\'erot type resonances in electronic transport. The intrinsic spin anisotropy of the helical edge states allows us to tune these resonances by changing the direction of the {$\vec B$} field while keeping its magnitude constant. This is in sharp contrast to the case of non-helical one dimensional electron gases with a parabolic dispersion, where similar resonances do appear in individual spin channels ($\uparrow$ and $\downarrow$) separately which, however, cannot be tuned by merely changing the direction of the {$\vec B$} field. These resonances provide a unique way to probe the helical nature of the theory.