Electronic Transport in Weyl Semimetals with a Uniform Concentration of Torsional Dislocations

Abstract

In this article, we consider a theoretical model for a type I Weyl semimetal, under the presence of a diluted uniform concentration of torsional dislocations. By means of a mathematical analysis for partial wave scattering (phase-shift) for the T-matrix, we obtain the corresponding retarded and advanced Green’s functions that include the effects of multiple scattering events with the ensemble of randomly distributed dislocations. Combining this analysis with the Kubo formalism, and including vertex corrections, we calculate the electronic conductivity as a function of temperature and concentration of dislocations. We further evaluate our analytical formulas to predict the electrical conductivity of several transition metal monopnictides, i.e., TaAs, TaP, NbAs, and NbP.

Electromagnetic coupling and transport in a topological insulator-graphene hetero-structure

“…the thermal conductivity tensor is defined by J = 0 12) , (34) and the Seebeck coefficient or thermopower is given by…”

“…These expressions are reduced to a more explicit form by introducing the spectral density function [12] A ξ (x, x ; E)…”

“…By following Ref. [12] (see Appendix C 3 for details) it is possible to include vertex corrections to the formalism. For that purpose, one of the k factors is replaced by the vertex correction Γ RA (k , E), that satisfies the Bethe-Salpeter equation (see Fig.…”

“…Following Ref. [12], as is shown in Appendix C 3, by considering the general form Γ RA (k , E) = γ(k , E)k , the relaxation time can be introduced with the relation…”

“…The presence of such charged impurities will induce a local distortion of the charge density of the 2D electron gas, leading to a non-trivial electromagnetic coupling between the TI and the graphene monolayer in the heterostructure. As a probe of this coupling, we further studied the electrical conductivity as a function of temperature, by including the scattering effects with the local electromagnetic field configuration via the Kubo linear response formalism [12][13][14]. We applied our theoretical results to model the electromagnetic coupling in heterostructures made of different TIs (PbTe, Bi 2 Te 3 , PbSe, PbS, Bi 2 Se 3 , TlBiSe 2 , TbPO 4 ).…”