Temperature and excitation energy dependence of Raman scattering in nodal line Dirac semimetal ZrAs_{2}

TL;DR

This study investigates how Raman scattering in ZrAs_{2} nodal line Dirac semimetals varies with temperature and excitation energy, revealing electron-phonon interactions and quantum interference effects.

Contribution

It provides the first detailed Raman analysis of ZrAs_{2}, identifying phonon symmetries, interference effects, and electron-phonon coupling in this nodal line semimetal.

Findings

Peak intensities depend on excitation wavelength, indicating quantum interference.

Fano resonance observed in the 171 cm^{-1} mode due to phonon-electronic continuum interaction.

Electron-phonon coupling influences phonon linewidth temperature dependence.

Abstract

We present a Raman study of ZrAs_{2} single crystals, a nodal line semimetal with symmetry-enforced Dirac-like band crossings. We identified the symmetry of phonon modes by polarized light measurements and comparison with calculated phonon frequencies. Significant dependence of peak intensities on the excitation wavelength was observed, indicating quantum interference effects. Phonon peaks in the spectra are superimposed on the electronic background, with quasi-elastic scattering observed for the 785 nm excitation. We identified the Fano shape of the 171 cm^{-1} Ag mode due to interference of the phonon state with the electronic continuum. The temperature dependence of phonon peaks linewidth indicates that the electron-phonon coupling plays an essential role in phonon decay.