Nernst thermopower of time-reversal breaking type-II Weyl semimetals

Abstract

Weyl semimetals host linear energy dispersions around Weyl nodes, as well as monopoles of Berry curvature in momentum space around these points. These features give rise to unique transport signatures in a Weyl semimetal, such as transverse transport without an applied magnetic field, known as anomalous transport. The type-II Weyl semimetal, recently experimentally demonstrated in several materials, is classified by a tilting of the Weyl nodes. This paper provides a theoretical study on thermoelectric transport in time-reversal breaking type-II Weyl semimetals. Our results examine the balance between anomalous and non-anomalous contributions to the Nernst effect when subject to an external magnetic field. We also show how increasing scattering times have on enhancing effect on thermoelectric transport in these materials. Since a temperature-dependent chemical potential has been theoretically shown to be paramount when considering anomalous transport, we also study how similar considerations impact the Nernst thermopower in the non-anomalous case. arXiv:1808.06580v2 [cond-mat.mes-hall]

Thermal transport for probing quantum materials

“…Similar to the anomalous Hall effect, even without external magnetic field, the Nernst effect can still emerge, called anomalous Nernst effect (ANE). ANE has been extensively studied in ferromagnetic metals, however, given the direct link between ANE and the Berry curvature, it has gained significant recent theoretical (123)(124)(125)(126)(127)(128)(129)(130)(131) and experimental (50)(51)(52)(132)(133)(134)(135)(136)(137)(138) attention in the field of topological Weyl semimetals (Figure 5b).…”

Thermoelectric transport of type-I, II, and III massless Dirac fermions in two-dimensional lattice model

“…(For instance, for the three-dimensional case, the studies on the minimal lattice model [40] were reported in Refs. [41,42].) In the continuous model, however, there is a subtlety of the momentum cut-off dependence, which hampers the study on the transport coefficients of all the three types in an equal-footing manner.…”