Thermoelectric transport properties of Floquet multi-Weyl semimetals

Abstract

We discuss the circularly polarized light (of amplitude $A_0$ and frequency $\omega$) driven thermo-electric 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 momentum independent contribution as observed for Floquet single WSMs. Apart from the non-trivial tuning of the Weyl node position $\pm Q \to \pm Q- A_0^{2n}/\omega$, our study reveals that the momentum independent terms result in leading order contribution in the conductivity tensor. This has the form of $n$ times the single WSMs results with effective chemical potential $\mu \to \mu -A_0^{2n}/\omega$. On the other hand, momentum dependent corrections lead to sub-leading order terms which are algebraic function of $\mu$ 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 $n\geq 2$ exhibit 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 $\omega$.