Séminaire DQMP - Spectroscopic signatures of topology in the particle-hole continuum of nodal-point semimetals

23.10.2018 13:00 – 14:30

In this talk, I will discuss how interesting features of topological origin in material band structures can be inferred by mapping the particle-hole continuum with spectroscopic probes. I will first highlight some simple geometric characteristics of the particle-hole continuum that arise due to nodal points in the electronic dispersion. These characteristics can be used to infer the presence of Weyl and Dirac nodes both below and above the Fermi level in bulk three-dimensional bands, and can thus serve as identifiers of topological content. I will then argue that resonant inelastic x-ray scattering (RIXS) is an appealing tool for directly accessing and studying the features of the particle-hole continuum of topological semimetals, especially in settings that preclude the use of other probes, such as, e.g., in magnetic fields. Going a step further, I will discuss how polarization-resolved RIXS can be used to visualize the Berry curvature distribution around Weyl nodes. Most importantly, I will show how this method can determine the topological charge of individual Weyl nodes, indicating its potential for a spectroscopic measurement of a quantized topological invariant. I will conclude with a quick overview of ongoing experimental and theoretical work.

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre