Torsional Chiral Magnetic Effect in a Weyl Semimetal with a Topological Defect

We propose a torsional response raised by a lattice dislocation in Weyl semimetals akin to a chiral magnetic effect; i.e., a fictitious magnetic field arising from a screw or edge dislocation induces a charge current. We demonstrate that, in sharp contrast to the usual chiral magnetic effect that vanishes in real solid state materials, the torsional chiral magnetic effect exists even for realistic lattice models, which implies the experimental detection of the effect via superconducting quantum interference device or nonlocal resistivity measurements in Weyl semimetal materials.

Figure 1

Ground state current $j$ induced by (a) an edge and (b) a screw dislocation with Burgers vector $b$.

Figure 2

(a) Schematic picture of the spectrum of the WSM with the screw dislocation. The black (white) bands along $E=\pm m_{k_z}^s$ represent the relatively higher (lower) density of state compared with that of the opposite energy $E=\mp m_{k_z}^s$. (b) Lattice with a pair of screw dislocations with opposite Burgers vectors. (c) Numerical result for the spectrum of the WSMs with a pair of screw dislocations. The blue curves are the envelope of the bulk spectrum. The opacity of the dots represents the expectation value of $|\mathit{\rho }-{\mathit{l}}^{\mathrm{dis}}{|}^2/L_x{L}_y$ (see the gray scale bar). In panels (c1)–(c3), the modes with this value smaller than 0.1, 0.15, and 0.2 are plotted. (d) Current density along $z$ direction, $j_z(x,y)$.

Figure 3

Experimental setup for the nonlocal transport due to the TCME. The thick red solid (blue dashed) line represents the (anti)dislocation line. The leads are attached at the black points $L_i(i=1,2,3,4,3^{\prime },4^{\prime })$. The lines $L_1{L}_2$, $L_3{L}_4$, and $L_{3^{\prime }}{L}_{4^{\prime }}$ are parallel and have the same length. Here, we suppose $L_1{L}_3<L_1{L}_{3^{\prime }}$. $V_i$ is the voltage at $L_i$, and $I_{12}$ is the current.