TITLE : 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.


Speaker: Tanay Nag, Uppsala University, Sweden

Venue: A1-3, South Campus, IIT Mandi

Date and Time: February 20th, 2023, 5:00pm