Calculations of the A_1 phonon frequency in photoexcited Tellurium

TL;DR

This paper presents calculations of how the A_1 phonon frequency in tellurium shifts with photoexcited carrier density, aiding interpretation of ultrafast pump-probe experiments to track carrier dynamics.

Contribution

It introduces a theoretical model linking phonon frequency shifts to photoexcited carrier density in tellurium, enhancing analysis of ultrafast spectroscopic data.

Findings

Phonon frequency varies with carrier density and amplitude.

Calculated shifts can interpret pump-probe experimental results.

Proposes using frequency shifts to monitor carrier evolution.

Abstract

Calculations of the A_1 phonon frequency in photoexcited tellurium are presented. The phonon frequency as a function of photoexcited carrier density and phonon amplitude is determined. Recent pump probe experiments are interpreted in the light of these calculatons. It is proposed that, in conjunction with measurements of the phonon period in ultra-fast pump-probe reflectivity experiments, the calculated frequency shifts can be used to infer the evolution of the density of photoexcited carriers on a sub-picosecond time-scale.