Speaker
Description
The minimal coupling of strain to Dirac and Weyl semimetals, and its modeling as a pseudo-gauge field has been extensively studied, resulting in several proposed topological transport signatures. However this insight does not carry over to Weyl semimetals of higher winding number, also known as multi-Weyl semimetals. Using the double-Weyl semimetal as an illustrative example, it is seen that the application of strain splits the higher winding number Weyl nodes to produce an anisotropic Fermi surface, thus acquiring nematic order. The emergent anisotropy modifies the semiclassical equations of motion, as well as the resulting transport signatures resulting in strain-dependent corrections. Specifically, the deformation of the Weyl nodes changes the electric current by an amount proportional to the covariant coupling of the strain tensor and the geometric tensor associated with the Weyl nodes. That is, strain produces geometric signatures rather than topological signatures in multi-Weyl semimetals. Further evidence for this idea is obtained by comparing and contrasting the ways in which simple and double-Weyl semimetals respond to dynamic strain (or sound waves). Finally, I will argue that the most general way to view strain is as a symmetry-breaking field rather than a pseudo-gauge field.
| Session Selection | Condensed Matter |
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