Ultrafast Band-Edge Carrier Dynamics in the Weyl Semiconductor Tellurium Microcrystal

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Tellurium microcrystals are key mid-infrared photonic materials and chiral semiconductors.
• Intrinsic relaxation dynamics are obscured by competing pathways under excitation.

Purpose of the Study:

• To directly probe band-edge resonances in tellurium microcrystals.
• To disentangle coupled electronic and structural dynamics using advanced spectroscopy.

Main Methods:

• Utilized mid-infrared asynchronous and interferometric transient absorption (MIR AI-TA) spectroscopy.
• Employed frequency-comb pulses near the band-edge (380 meV).
• Applied a global spectro-temporal model for data analysis.

Main Results:

• Identified two distinct relaxation components: a fast (1-2 ps) and a slow (∼50 ps).
• Assigned the fast component to phonon-assisted hole redistribution and Peierls distortion recovery.
• Attributed the slow component to band-edge electron-hole recombination.

Conclusions:

• MIR AI-TA spectroscopy can quantitatively resolve coupled electronic and structural dynamics.
• Provides new insights into relaxation mechanisms in narrow-bandgap semiconductors.
• Highlights the potential of tellurium microcrystals in photonic applications.