Weyl-Kondo semimetals in nonsymmorphic systems

TL;DR

This paper explores how nonsymmorphic symmetries and strong correlations in heavy fermion systems lead to Weyl-Kondo semimetals with unique electronic properties, expanding understanding of topological phases in correlated materials.

Contribution

It demonstrates how nonsymmorphic space-group symmetry and correlations produce Weyl nodes at the Fermi energy in heavy fermion systems, with analysis of tilted Weyl-Kondo phases.

Findings

Weyl nodes are pinned to the Fermi energy due to symmetry and correlations.

Nonsymmorphic symmetries enable the formation of Weyl nodal excitations.

Tilted Weyl-Kondo solutions relate to spontaneous Hall effects in specific materials.

Abstract

There is considerable current interest to explore electronic topology in strongly correlated metals, with heavy fermion systems providing a promising setting. Recently, a Weyl-Kondo semimetal phase has been concurrently discovered in theoretical and experimental studies. The theoretical work was carried out in a Kondo lattice model that is time-reversal invariant but inversion-symmetry breaking. In this paper, we show in some detail how nonsymmorphic space-group symmetry and strong correlations cooperate to form Weyl nodal excitations with highly reduced velocity and pin the resulting Weyl nodes to the Fermi energy. A tilted variation of the Weyl-Kondo solution is further analyzed here, following the recent consideration of such effect in the context of understanding a large spontaneous Hall effect in Ce$_3$Bi$_4$Pd$_3$ (Dzsaber et al., arXiv:1811.02819). We discuss the implications of our results for the enrichment of the global phase diagram of heavy fermion metals, and for the space-group symmetry enforcement of topological semimetals in other strongly correlated settings.