Magneto-transport signatures in periodically-driven Weyl and multi-Weyl semimetals

Abstract

We investigate the influence of a time-periodic driving (for example, by shining circularly polarized light) on three-dimensional Weyl and multi-Weyl semimetals, in the planar Hall and planar thermal Hall set-ups. We incorporate the effects of the drive by using the Floquet formalism in the large frequency limit. We evaluate the longitudinal magneto conductivity, planar Hall conductivity, longitudinal thermo-electric coefficient, and transverse thermo-electric coefficient, using the semi-classical Boltzmann transport equations. We demonstrate the explicit expressions of these transport coefficients in certain limits of the parameters, where it is possible to perform the integrals analytically. We cross-check our analytical approximations by comparing the physical values with the numerical results, obtained directly from the numerical integration of the integrals. The answers obtained show that the topological charges of the corresponding semimetals have profound signatures in these transport properties, which can be observed in experiments. Contents I. Introduction 1 II. Model and Formalism 3 A. Boltzmann Formalism 4 B. Time-periodic Driving 4 III. Longitudinal and Transverse Magneto-Conductivities 5 IV. Longitudinal and Transverse Thermo-Electric Coefficients 9 V. Discussions and Physical Interpretation of the Results 13

Chiral anomaly induced magnetoconductances in an irradiated type-I Weyl semimetal

“…In figure 10, one witnesses the fluctuating behavior of σ L when the time dependent field strength is turned on gradually. Though there are many studies of magneto-transport in Weyl systems under periodic driving [25,30,31], the present study uses a combination of dc and ac fields which is first of its kind, as per the best of the authors' knowledge. Based on this preliminary results and discussions, one can always build up further understanding incorporating additional complexities like using fully anisotropic BTE for considering anisotropy due to coupling between B and Ω [32,33], considering the effect of intra-node scattering [34] or incorporating the orbital magnetic moments [34,35] etc.…”

“…Based on this preliminary results and discussions, one can always build up further understanding incorporating additional complexities like using fully anisotropic BTE for considering anisotropy due to coupling between B and Ω [32,33], considering the effect of intra-node scattering [34] or incorporating the orbital magnetic moments [34,35] etc. Dynamics of our periodically driven problem can be analyzed using adiabatic-impulse approximation or Floquet formalisms for small and high frequency quenches respectively [25,30,36]. One can also probe the thermal and Nernst conductivities under the same field set up [25,37] or investigate the response from multi-Weyl systems [25,30,37,38].…”

“…Dynamics of our periodically driven problem can be analyzed using adiabatic-impulse approximation or Floquet formalisms for small and high frequency quenches respectively [25,30,36]. One can also probe the thermal and Nernst conductivities under the same field set up [25,37] or investigate the response from multi-Weyl systems [25,30,37,38]. We should mention here that the tendency of σ L to become singular as C → 1 is an artifact of using the continuum model and we have plans to later use a more realistic lattice model possibly incorporating beyond nearest-neighbor electron hoppings and reinvestigate this problem.…”