Probing anharmonic phonons in WS2 van der Waals crystal by Raman spectroscopy and machine learning

Chisom Okeke; Isaac Juma; Antonio Cobarrubia; Nicholas Schottle; Hisham Maddah; Mansour Mortazavi; Sanjay K Behura

doi:10.1016/j.isci.2023.107174

Probing anharmonic phonons in WS₂ van der Waals crystal by Raman spectroscopy and machine learning

iScience. 2023 Jun 18;26(7):107174. doi: 10.1016/j.isci.2023.107174. eCollection 2023 Jul 21.

Authors

Chisom Okeke¹, Isaac Juma¹, Antonio Cobarrubia^{2

3}, Nicholas Schottle², Hisham Maddah⁴, Mansour Mortazavi¹, Sanjay K Behura²

Affiliations

¹ Department of Mathematics and Computer Science and Department of Chemistry and Physics, University of Arkansas at Pine Bluff, 1200 N. University Drive, Pine Bluff, AR 71601, United States.
² Department of Physics, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States.
³ Computational Science Research Center, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States.
⁴ Department of Chemical Engineering, King Abdulaziz University, Rabigh 21911, Saudi Arabia.

Abstract

Understanding the optothermal physics of quantum materials will enable the efficient design of next-generation photonic and superconducting circuits. Anharmonic phonon dynamics is central to strongly interacting optothermal physics. This is because the pressure of a gas of anharmonic phonons is temperature dependent. Phonon-phonon and electron-phonon quantum interactions contribute to the anharmonic phonon effect. Here we have studied the optothermal properties of physically exfoliated WS₂ van der Waals crystal via temperature-dependent Raman spectroscopy and machine learning strategies. This fundamental investigation will lead to unveiling the dependence of temperature on in-plane and out-of-plane Raman shifts (Raman thermometry) of WS₂ to study the thermal conductivity, hot carrier diffusion coefficient, and thermal expansion coefficient.

Keywords: Applied sciences; Nanomaterials; machine learning.