We are pleased to inform you that the seminar will be held as follows.
Please see below for details. We look forward to your participation.

Title：Raman scattering spectroscopy as a probe of the magnetic Weyl semimetal state.
Speaker：Prof. Natalia Drichko
　　　　 Johns Hopkins University

Day：Friday, October 3, 2025　3:00 PM ～ 4:30 PM  (JST)
Venue：The University of Tokyo Faculty of Science Bldg.1 #913

In magnetic Weyl semimetals, the intrinsic anomalous Hall effect arises from non-zero Berry curvature near the Weyl nodes. However, to clearly establish Weyl semimetal evidence of the topological electronic structure and a particular form of time reversal symmetry breaking order is needed.

In this presentation, I demonstrate how Raman scattering spectroscopy can be used to probe low-frequency electronic structure and magnetism in Weyl semimetals using examples of Nd2Ir2O7 and V1/3NbS2. Frequency dependence of electronic Raman scattering within Weyl nodes is proportional to the density of states and depends on dimensionality, thus revealing the linear q-dependence of the density of states down to low frequencies unaccessible for the most part with other optical techniques. Simultaneously probing magnetic Raman scattering identifies a magnetic phase transition. In this way, polarization-dependent electronic and magnetic Raman scattering demonstrates the presence of the band structure and form of time reversal symmetry breaking necessary to realize a Weyl semimetal state.  I will also show how scattering of optical phonons on the electrons in a semimetal can be a tool to probe the electronic bands.