Topological Signatures in Nodal Semimetals through Neutron Scattering

TL;DR

This paper proposes a theoretical framework showing how neutron scattering can reveal topological features in nodal semimetals, including Weyl nodes and chiral anomalies, by analyzing the dynamical structure factor.

Contribution

It introduces a new formula for the dynamical structure factor in topological nodal metals and links neutron response signatures to topological properties.

Findings

Neutron scattering responses are sensitive to topological nodal features.

Weyl node locations and Fermi velocities influence neutron spectral signatures.

Chiral anomaly signatures can be detected via neutron spectral responses.

Abstract

Topological nodal semimetals are known to host a variety of fascinating electronic properties due to the topological protection of the band-touching nodes. Neutron scattering, despite its power in probing elementary excitations, has not been routinely applied to topological semimetals, mainly due to the lack of an explicit connection between the neutron response and the signature of topology. In this work, we theoretically investigate the role that neutron scattering can play to unveil the topological nodal features: a large magnetic neutron response with spectral non-analyticity can be generated solely from the nodal bands. A new formula for the dynamical structure factor for generic topological nodal metals is derived. For Weyl semimetals, we show that the locations of Weyl nodes, the Fermi velocities and the signature of chiral anomaly can all leave hallmark neutron spectral responses. Our work offers a neutron-based avenue towards probing bulk topological materials.