Dislocation defect as a bulk probe of monopole charge of multi-Weyl semimetals

TL;DR

This paper proposes using a screw dislocation defect in multi-Weyl semimetals as a bulk probe to directly measure the monopole charge through conductance measurements, linking defect-induced effects to topological properties.

Contribution

It introduces a novel method to determine the monopole charge in multi-Weyl semimetals via conductance signatures caused by dislocation defects, providing a practical experimental approach.

Findings

Dislocation acts as a pseudo-magnetic flux tube revealing monopole charge.

Conductance maxima ratios encode the monopole charge information.

Effective pseudo-magnetic flux can be deduced from conductance peak positions.

Abstract

Multi-Weyl semimetals feature band crossings with the dispersion that is, in general, linear in only one direction, and as a consequence their band structure is characterized by the monopole charge $n$ which can be greater than one. We show that a single screw dislocation defect oriented in the direction connecting the nodal points, which acts as an effective pseudo-magnetic flux tube, can serve as a direct probe of the monopole charge $n\geq1$ characterizing the bulk band structure of a multi-Weyl semimetal. To this end, as a proof of principle, we propose a rather simple mesoscopic setup in which the monopole charge leaves a direct imprint on the conductance measured in the plane perpendicular to the dislocation. In particular, the ratio of the positions of the neighboring maxima in the conductance as a function of the gate voltage can serve to deduce the monopole charge, while the value of the effective pseudo-magnetic flux can be extracted from the position of a conductance maximum. We expect that these findings will prompt further studies on the role of multiple dislocations, as well as other topological lattice defects, such as grain boundaries and disclinations, in topological nodal materials.