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

Area of Science:

• Quantum materials science
• Optothermal physics
• Condensed matter physics

Background:

• Anharmonic phonon dynamics is key to optothermal physics, influencing temperature-dependent pressure.
• Phonon-phonon and electron-phonon interactions drive anharmonic phonon effects.

Purpose of the Study:

• Investigate the optothermal properties of tungsten disulfide (WS₂) van der Waals crystals.
• Establish temperature-dependent Raman shifts for WS₂ for advanced thermometry.
• Determine thermal conductivity, hot carrier diffusion, and thermal expansion coefficients.

Main Methods:

• Utilized physically exfoliated WS₂.
• Employed temperature-dependent Raman spectroscopy.
• Applied machine learning strategies for data analysis.

Main Results:

• Unveiled the temperature dependence of in-plane and out-of-plane Raman shifts in WS₂.
• Established a foundation for Raman thermometry in WS₂.
• Provided insights into thermal transport properties.

Conclusions:

• Understanding optothermal physics in WS₂ is vital for next-generation photonic and superconducting circuits.
• The study provides fundamental insights into anharmonic phonon dynamics and thermal properties.
• This research paves the way for efficient design of optoelectronic devices.