Probing lattice dynamics and electron-phonon coupling in topological nodal-line semimetal ZrSiS

TL;DR

This study investigates the lattice vibrations and electron-phonon interactions in the topological nodal-line semimetal ZrSiS using Raman spectroscopy and high-pressure techniques, revealing complex electron-phonon dynamics and pressure-induced phase transitions.

Contribution

It provides detailed experimental insights into the phonon behavior and structural transitions in ZrSiS, advancing understanding of topological nodal-line semimetals.

Findings

Complex interplay of electron and phonon degrees of freedom.

Pressure-induced structural and electronic phase transitions.

Identification of vibrational anomalies and phase coexistence.

Abstract

Topological materials provide an exclusive platform to study the dynamics of relativistic particles in table-top experiments and offer the possibility of wide-scale technological applications. ZrSiS is a newly discovered topological nodal-line semimetal and has drawn enormous interests. In this report, we have investigated the lattice dynamics and electron-phonon interaction in single crystalline ZrSiS using Raman spectroscopy. Polarization and angle resolved measurements have been performed and the results have been analyzed using crystal symmetries and theoretically calculated atomic vibrational patterns along with phonon dispersion spectra. Wavelength and temperature dependent measurements show the complex interplay of electron and phonon degrees of freedom, resulting in resonant phonon and quasielastic electron scatterings through inter-band transitions. Our high-pressure Raman studies reveal vibrational anomalies, which were further investigated from the high-pressure synchrotron x-ray diffraction (HPXRD) spectra. From HPXRD, we have clearly identified pressure-induced structural transitions and coexistence of multiple phases, which also indicate possible electronic topological transitions in ZrSiS. The present study not only provides the fundamental information on the phonon subsystem, but also sheds some light in understanding the topological nodal-line phase in ZrSiS and other iso-structural systems.