Spin and charge transport in topological nodal-line semimetals

TL;DR

This paper investigates the unique spin and charge transport phenomena in topological Weyl nodal-line semimetals, revealing nearly fully spin-polarized currents and unusual resonances due to surface states in specific junction configurations.

Contribution

It provides a detailed analysis of transport behavior in NLSs with a focus on the effects of nodal loop orientation and surface states, highlighting phenomena not previously characterized.

Findings

Nearly fully spin-polarized transmitted current when loop is parallel to interfaces

Existence of a spin orientation causing total reflection of incident electrons

Unusual resonance of half transmission involving surface states

Abstract

We study transport properties of topological Weyl nodal-line semimetals(NLSs). Starting from a minimal lattice model with a single nodal loop, and by focusing on a normal-metal-NLS-normal-metal junction, we investigate the dependence of the novel transport behavior on the orientation of the nodal loop. When the loop is parallel to the junction interfaces, the transmitted current is found to be nearly fully spin-polarized. Correspondingly, there exists a spin orientation, along which the incident electrons would be totally reflected. An unusual resonance of half transmission with the participation of surface states also occurs for a pair of incident electrons with opposite spin orientations. All these phenomena have been shown to originate from the existence of a single forward-propagating mode in the NLS of the junction, and argued to survive in more generic multi-band Weyl NLSs.