Anomalous thermoelectric phenomena in lattice models of multi-Weyl semimetals

Abstract

The thermoelectric transport coefficients are calculated in a generic lattice model of multi-Weyl semimetals with a broken time-reversal symmetry by using the Kubo's linear response theory. The contributions connected with the Berry curvature-induced electromagnetic orbital and heat magnetizations are systematically taken into account. It is shown that the thermoelectric transport is profoundly affected by the nontrivial topology of multi-Weyl semimetals. In particular, the calculation reveals a number of thermal coefficients of the topological origin which describe the anomalous Nernst and thermal Hall effects in the absence of background magnetic fields. Similarly to the anomalous Hall effect, all anomalous thermoelectric coefficients are proportional to the integer topological charge of the Weyl nodes. The dependence of the thermoelectric coefficients on the chemical potential and temperature is also studied.

Linear magnetochiral transport in tilted type-I and type-II Weyl semimetals

“…This has a significant impact on the dynamics of the electron wave-packets in the WSM lattice, particularly in the presence of parallel electric and magnetic fields (a finite E · B term). This results in a plethora of interesting magnetoconductivity (MC) and magneto-thermal transport properties in WSM, which have been extensively investigated theoretically [26,27,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]. For example, Negative magnetoresistance (MR) has been observed in several WSMs, including all the members of the TaAs family [34][35][36][37][38] and WSMs derived from 3D-Dirac semimetals [6,[30][31][32], among others.…”

Fingerprints of the conformal anomaly in the thermoelectric transport in Dirac and Weyl semimetals

“…From the early research it was known that semiconductors and semimetals are the best candidates to generate large figures of merit in thermopower, with bismuth, an almost compensated semimetal, holding the record for metallic compounds 16 . Dirac and Weyl semimetals belong naturally to the family of good thermo-electric materials and their thermoelectric properties are now at the center of interest in experimental and theoretical research 13,14,[17][18][19][20][21][22][23][24][25] . Giant values of the anomalous Nernst effect are been systematically reported in the newly-discovered magnetic Weyl semimetals.…”

Thermopower in an anisotropic two-dimensional Weyl semimetal

“…[10][11][12][13][14][15][16] Moreover, the 3D Dirac and Weyl materials give rise to unsaturated thermopower, which in turn leads to large thermoelectric figure-of-merit in the presence of a quantizing magnetic field. 17 Despite much work on the transport properties in Dirac/Weyl materials, [18][19][20][21][22][23][24][25][26][27][28][29] the thermoelectric properties in relatively new 2D anisotropic Dirac materials such as VO 2 /TiO 3 , 30-32 organic salts, 33,34 and deformed graphene, [35][36][37][38] having a quadratic dispersion in one direction and a linear dispersion along the orthogonal direction, have not been explored so far in details. This is in part because there are lack of natural materials with such anisotropic dispersion and in part because the anisotropy leads to complexities in finding the analytical expressions for relevant thermoelectric coefficients involving different scattering mechanism, as compared to the in-plane and out-of-plane anisotropy in double-Weyl materials.…”