Topological transports in Weyl semi-metals

In recent years, the electronic and thermal transport properties of various topological systems specially Weyl semimetal (WSMs) have attracted tremendous attention due to their Fermi arc surface states. For example, in the absence (presence) of the magnetic field, the non-trivial Berry curvatures (chiral anomaly and chiral magnetic effect) result in anomalous Hall conductivity (negative magneto-resistance). We show the universal scaling of magneto-Hall conductivity and thermo-electric conductivity, respectively assisted by the chiral anomaly and chiral magnetic effect,  for multi-WSMs (mWSMs) in planar Hall set up [1]. We investigate the effect of tilt and intriguing Fermi surface properties of mWSMs in the ballistic limit through the Magnus Hall conductivity [2,3]. We further extend our analysis to the quantum limit with Landau levels where we study the three-dimensional quantum Hall effect [4]. Apart from the above first-order transport signatures, we show that the topological charge of the activated Weyl nodes can be directly captured by the quantized circular photogalvanic effect which is a second-order response [5,6]. We then connect our predictions, based on models, with the recent theoretical as well as experimental findings obtained from real materials. Finally, we summarize the possible applicability of our framework to analyze various response properties in more realistic and experimentally viable platforms. 

[1] Magneto-transport phenomena of type-I multi-Weyl semimetals in co-planar setups, T. Nag and S. Nandy, J. Phys.: Condens. Matter 33 (2021) 075504.

[2] Topological Magnus responses in two and three-dimensional systems, S. K. Das, T. Nag, and S. Nandy, Phys. Rev. B 104, 115420 (2021).

[3] Distinct signatures of particle-hole symmetry breaking in transport coefficients for generic multi-Weyl semimetals, T. Nag, and D. M. Kennes,  Phys. Rev. B 105, 214307 (2022)

[4] Understanding the three-dimensional quantum Hall effect in generic multi-Weyl semimetals, F. Xiong, C. Honerkamp, D. M. Kennes, and T. Nag,  Phys. Rev. B 106,
045424 (2022).

[5] Electronic structure and unconventional non-linear response in double Weyl semimetal SrSi_2, B. Sadhukhan and T. Nag, Phys. Rev. B 104, 245122 (2021).

[6] Role of time-reversal symmetry and tilting in circular photogalvanic responses, B. Sadhukhan and T. Nag, Phys. Rev. B 103, 144308 (2021).