ウルフト構造半導体テルル微結晶における超高速バンド端キャリアダイナミクス

Rod-shaped tellurium microcrystals are promising mid-infrared photonic materials and a prototypical chiral (Weyl) semiconductor, yet intrinsic band-edge relaxation at room temperature is often masked by hot-carrier and photothermal pathways under above-gap excitation. Here, we employ mid-infrared asynchronous and interferometric transient absorption (MIR AI-TA) spectroscopy with frequency-comb pulses centered near the band-edge (380 meV) to directly interrogate two band-edge resonances. The time- and frequency-resolved AI-TA data reveal a fast component characterized by a time constant of 1-2 ps and a long-lived component with a time constant of ∼50 ps, common to both resonances. A global spectro-temporal model assigns the fast component to phonon-assisted redistribution of valence holes coupled to recovery of pump-induced Peierls distortion, while the slow component corresponds to band-edge electron-hole recombination. These results demonstrate that MIR AI-TA can quantitatively disentangle coupled electronic and structural dynamics in narrow-bandgap semiconductors.