Zero Frequency Nonperturbative Response Across a Topological Phase Transition

This work studies the identification of nontrivial topology of topological semimetals in quantum materials. Current diagnostic tools, such as angle-resolved photoemission spectroscopy and longitudinal magnetoresistance, can be used to identify nontrivial topology, however, strongly correlated regimes require higher energy resolutions than these probes can provide. We computationally study the current response of theoretical models to identify nontrivial topology in strongly correlated topological semimetals using intense zero frequency field excitation and calculating the current response. The Weyl Kondo semimetal model (WKSM) adequately captures the topologically nontrivial topological semimetal behavior of Ce3Bi4Pd3 and the topologically trivial Kondo insulator behavior of Ce3Bi4Pt3 through a single tuning parameter. We study the zero frequency response across the two states' topological phase transition between the Weyl semimetal and Kondo insulator phases using DC light in varying directions and intensities, by calculating the current using a nonperturbative theoretical formalism. We study differences between the WKSM and Kondo insulator that may be differentiating signatures of topological states. This theoretical research relates to experimental work on both the known Ce3Bi4Pd3 (WKSM) and Ce3Bi4Pt3 (Kondo insulator) and to possibly diagnose topological states of new candidate materials.