Signatures of van Hove singularities in the anisotropic in-plane optical conductivity of the topological semimetal Nb3SiTe6

We present a temperature-dependent infrared spectroscopy study on the layered topological semimetal Nb3SiTe6 combined with density-functional theory calculations of the electronic band structure and optical conductivity. Our results reveal an anisotropic behavior of the in-plane (ac-plane) optical conductivity, with three pronounced excitations located at around 0.15, 0.28, and 0.41 eV for the polarization of the incident radiation along the c axis. These excitations are well reproduced in the theoretical spectra. Based on the ab initio results, the excitations around 0.15 and 0.28 eV are interpreted as fingerprints of van Hove singularities in the electronic band structure and compared to the findings for other topological semimetals.

Automated summary

We conducted a temperature-dependent infrared spectroscopy study on the layered topological semimetal Nb3SiTe6 and performed density-functional theory calculations to investigate its electronic band structure and optical conductivity. Our results showed an anisotropic behavior of the in-plane optical conductivity, with three prominent excitations located at around 0.15, 0.28, and 0.41 eV when the incident radiation was polarized along the c axis. These excitations were well reproduced in the theoretical spectra. Based on the ab initio results, we interpreted the excitations around 0.15 and 0.28 eV as fingerprints of van Hove singularities in the electronic band structure and compared them to findings in other topological semimetals.