Electronic properties of strained double-Weyl systems

TL;DR

This paper investigates how strain affects the electronic properties of double-Weyl systems, revealing that strains can induce nematic order and alter wavepacket dynamics, with implications for topological materials.

Contribution

It demonstrates that strains do not generally act as gauge potentials in double-Weyl systems and shows how strains can induce nematic order and modify wavepacket behavior.

Findings

Strains do not generally couple as pseudoelectromagnetic gauge potentials.

Strains can induce nematic order, splitting double-Weyl nodes.

Strains modify wavepacket velocities and induce spin polarization.

Abstract

The effects of strains on the low-energy electronic properties of double-Weyl phases are studied in solids and cold-atom optical lattices. The principal finding is that deformations do not couple, in general, to the low-energy effective Hamiltonian as a pseudoelectromagnetic gauge potential. The response of an optical lattice to strains is simpler, but still only one of several strain-induced terms in the corresponding low-energy Hamiltonian can be interpreted as a gauge potential. Most interestingly, the strains can induce a nematic order parameter that splits a double-Weyl node into a pair of Weyl nodes with the unit topological charges. The effects of deformations on the motion of wavepackets in the double-Weyl optical lattice model are studied. It is found that, even in the undeformed lattices, the wavepackets with opposite topological charges can be spatially split. Strains, however, modify their velocities in a very different way and lead to a spin polarization of the wavepackets.