Pressure-Induced Excitations in the Out-of-Plane Optical Response of the Nodal-Line Semimetal ZrSiS

Author(s)
J. Ebad-Allah, S. Rojewski, M. Vöst, G. Eickerling, W. Scherer, E. Uykur, Raman Sankar, L. Varrassi, C. Franchini, K. -H. Ahn, J. Kunes, C. A. Kuntscher
Abstract

The anisotropic optical response of the layered, nodal-line semimetal ZrSiS at ambient and high pressure is investigated by frequency-dependent reflectivity measurements for the polarization along and perpendicular to the layers. The highly anisotropic optical conductivity is in very good agreement with results from density-functional theory calculations and confirms the anisotropic character of ZrSiS. Whereas the in-plane optical conductivity shows only modest pressure-induced changes, we found strong effects on the out-of-plane optical conductivity spectrum of ZrSiS, with the appearance of two prominent excitations. These pronounced pressure-induced effects can neither be attributed to a structural phase transition according to our single-crystal x-ray diffraction measurements, nor can they be explained by electronic correlation and electron-hole pairing effects, as revealed by theoretical calculations. Our findings are discussed in the context of the recently proposed excitonic insulator phase in ZrSiS.

Organisation(s)
Computational Materials Physics
External organisation(s)
Tanta University, Universität Stuttgart, Academia Sinica Institute of Astronomy and Astrophysics, Università degli Studi di Bologna, Technische Universität Wien, Universität Augsburg, Czech Academy of Sciences
Journal
Physical Review Letters
Volume
127
No. of pages
6
ISSN
0031-9007
DOI
https://doi.org/10.1103/PhysRevLett.127.076402
Publication date
08-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
103015 Condensed matter, 103018 Materials physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/pressureinduced-excitations-in-the-outofplane-optical-response-of-the-nodalline-semimetal-zrsis(bf6fe48e-c539-4786-ab08-5f5351b6b1d3).html