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Physics Events

Physics Colloquium: The Nonlinear Electrodynamics of Weyl Semimetals

Thursday, June 6, 2019

3:30 PM-4:30 PM

Darius H Torchinsky, PhD, Temple University

At the heart of the Weyl semimetal are massless, chiral quasiparticles that derive from electronic band-crossings split by either spatial inversion or time-reversal symmetry breaking. The resulting nodal points in the bulk band structure serve as sources and sinks of units of Berry curvature or “topological charge” that are responsible for the phenomenology usually associated with these materials, including open Fermi arc surface states, negative magnetoresistance, and the chiral anomaly. However, Weyl semimetals with acentric crystal structures can also support second order nonlinear optical responses that reveal their unique band structure in surprising ways. In this talk, I will discuss our recent observation of a quantized photogalvanic effect in the structurally chiral Weyl semimetal RhSi measured using nonlinear optical techniques that reports its topological charge directly and also share our ongoing spectroscopic studies of the second harmonic generation response of this material.

Contact Information

Professor Goran Karapetrov

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Disque Hall, Room 919, 32 South 32nd Street, Philadelphia, PA 19104


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