Thermoelectric transport properties of Floquet multi-Weyl semimetals
Physical Review B
We discuss the circularly polarized light (of amplitude A0 and frequency ω) driven thermoelectric transport properties of type-I and type-II multi-Weyl semimetals (mWSMs) in the high-frequency limit. Considering the low-energy model, we employ the Floquet-Kubo formalism to compute the thermal Hall and Nernst conductivities for both types of mWSMs. We show that the anisotropic nature of the dispersion for arbitrary integer monopole charge n>1 plays an important role in determining the effective Fermi surface behavior; interestingly, one can observe momentum-dependent corrections in Floquet mWSMs in addition to the momentum-independent contribution as observed for Floquet single WSMs. Apart from the nontrivial tuning of the Weyl node position ±Q→±Q-A02n/ω, our study reveals that the momentum-independent terms result in leading order contributions in the conductivity tensor. This has the form of n times the single-WSM results with effective chemical potential μ→μ-A02n/ω. On the other hand, momentum-dependent corrections lead to subleading order terms which are an algebraic function of μ and are present for n>1. Remarkably, this analysis further allows us to distinguish type-I mWSMs from their type-II counterparts. For type-II mWSMs, we find that the transport coefficients for n≥2 exhibit an algebraic dependence on the momentum cutoff in addition to the weak logarithmic dependence as noticed for n=1 WSMs. We demonstrate the variation and qualitative differences of transport coefficients between type-I and type-II mWSM as a function of external driving parameter ω.
Nag, Tanay; Menon, Anirudha; and Basu, Banasri, "Thermoelectric transport properties of Floquet multi-Weyl semimetals" (2020). ISI Best Publications. 81.