Optical studies of carrier and phonon dynamics in Ga_{1-x}Mn_{x}As

TL;DR

This study uses time-resolved optical techniques to investigate how carriers and phonons behave in Ga_{1-x}Mn_{x}As layers, revealing effects of Mn and hole concentrations on optical absorption and phonon dephasing.

Contribution

It provides new insights into carrier and phonon dynamics in Ga_{1-x}Mn_{x}As, highlighting the influence of Mn and hole concentrations on optical and vibrational properties.

Findings

Band gap renormalization becomes significant with higher Mn concentration.

Increasing Mn and hole levels lead to faster LO phonon dephasing.

Direct observation of lattice vibrations via electro-optic sampling.

Abstract

We present a time-resolved optical study of the dynamics of carriers and phonons in Ga_{1-x}Mn_{x}As layers for a series of Mn and hole concentrations. While band filling is the dominant effect in transient optical absorption in low-temperature-grown (LT) GaAs, band gap renormalization effects become important with increasing Mn concentration in Ga_{1-x}Mn_{x}As, as inferred from the sign of the absorption change. We also report direct observation on lattice vibrations in Ga1-xMnxAs layers via reflective electro-optic sampling technique. The data show increasingly fast dephasing of LO phonon oscillations for samples with increasing Mn and hole concentration, which can be understood in term of phonon scattering by the holes.