Proposal for detecting nodal-line semimetal surface-states with resonant spin-flipped reflection

TL;DR

This paper proposes a spin-resolved transport method to directly detect drumhead-like surface states in topological nodal-line semimetals through resonant spin-flipped reflection, offering a robust experimental signature.

Contribution

It introduces a novel detection scheme using spin-resolved transport and resonant reflection to identify surface states in nodal-line semimetals, demonstrated with numerical calculations for HgCr$_2$Se$_4$.

Findings

Resonant spin-flipped reflection indicates the presence of surface states.

Zero-energy conductance peaks serve as signatures of drumhead surface states.

The detection scheme is robust against dispersive surface states and disorder.

Abstract

Topological nodal-line semimetals are predicted to exhibit unique drumhead-like surface states (DSS). Yet, a direct detection of such states remains a challenge. Here, we propose spin-resolved transport in a junction between a normal metal and a spin-orbit coupled nodal-line semimetal as the mechanism for their detection. Specifically, we find that in such a device, the DSS induce resonant spin-flipped reflection. This effect can be probed by both vertical spin transport and lateral charge transport between anti-parallel magnetic terminals. In the tunneling limit of the junction, both spin and charge conductances exhibit a resonant peak around zero energy, providing a unique evidence of the DSS. This signature is robust to both dispersive DSS and interface disorder. Based on numerical calculations, we show that the scheme can be implemented in the topological semimetal HgCr$_2$Se$_4$.