Tuning Quantum States at Chirality-Reversed Planar Interface in Weyl Semimetals using an Interstitial Layer

TL;DR

This paper demonstrates how a magnetic interstitial layer can tune the electronic and spin properties of Weyl semimetals at a chirality-reversed planar interface, enabling control over bound states and electron transmission.

Contribution

It introduces a method to tune Weyl semimetal interface states using an interstitial magnetic layer, highlighting control via electrostatic and magnetic potentials.

Findings

Magnetic interstitial layers control Fermi-arc shapes.

Electrostatic and magnetic potentials influence electron transmission.

Spin-filtering occurs across the interface for certain magnetic conditions.

Abstract

The electronic band structure of Weyl semimetals possesses pairs of linear band crossings, called Weyl nodes, characterized by opposite chirality charges associated with each node. The momentum space position of the nodes can reverse across a planar interface and these host Fermi-arc-like bound states, in addition to scattering states. We show that a magnetic interstitial layer can tune these states in three distinct ways. The electrostatic potential and one of the in-plane magnetic potential components control the shape of the bound state Fermi-arcs. For moderate values of the same in-plane magnetic potential electrons are spin-filtered across the interface, while both the in-plane magnetic components and the electrostatic potential control the transmission of electrons. The ratio of in-plane to out-of-plane magnetic components can be used to turn on or turn off the magnetic potential effects, since the latter does not affect the interface states. The tunability arises from spin-momentum locking and chirality reversal at the interface. Thus, the effects can mix or interchange depending on the specific material but the states will remain tunable.