Ultrafast Photocurrents in a topological insulator - an inside view

by Dr. Hadas Soifer

TAU

at Condensed Matter Seminar

Mon, 02 May 2022, 11:30
Sacta-Rashi Building for Physics (54), room 207

Abstract

In this talk I will discuss how we use time-resolved ARPES to study coupling of light to topological electronic states, and in particular gain better understanding of photocurrent generation in topological insulators. Photocurrents in topological materials have been associated with topological properties of the electronic bands, such as the Berry connection. However, despite some experimental demonstrations, it has remained unclear what part the topology actually plays in the process, and what stems from other contributions. We used time- and angle-resolved photoemission spectroscopy (trARPES) to resolve photocurrents in the excited electronic states of a topological insulator [1]. Furthermore, by analyzing the rise times of the population following the optical excitation, we gained a complete view of the occupied and unoccupied electronic states, and how they are coupled by the light. Our work provides a microscopic understanding of how to control photocurrents in materials with spin-orbit coupling and broken inversion symmetry, and paves the way to control of currents in topological states.
[1] H. Soifer et al., Phys. Rev. Lett., 122, 167401 (2019).

Created on 29-04-2022 by Meidan, Dganit (dganit)
Updaded on 29-04-2022 by Meidan, Dganit (dganit)