第3回「相関設計」セミナーを10月3日(金)に開催します。

Title: Raman scattering spectroscopy as a probe of the magnetic Weyl semimetal state.

Speaker: Prof. Natalia DrichkoJohns Hopkins University

Date and time: October 3, 2025 (Friday) 15:00-16:30 (JST)

Location: Room 913, Building 1, Faculty of Science, University of Tokyo

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 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.