Recombination kinetics of a dense electron-hole plasma in strontium titanate

TL;DR

This study examines the recombination dynamics of a dense electron-hole plasma in SrTiO3, revealing two distinct decay processes and proposing a polaron interaction model to explain the kinetics.

Contribution

It provides the first detailed analysis of nanosecond-scale recombination kinetics in SrTiO3, identifying two decay components and introducing a polaron-based interpretation.

Findings

Two decay components with different dynamics identified

Recombination modeled as bimolecular and unimolecular processes

Polaron interactions proposed as key to kinetics

Abstract

We investigated the nanosecond-scale time decay of the blue-green light emitted by nominally pure SrTiO$_3$ following the absorption of an intense picosecond laser pulse generating a high density of electron-hole pairs. Two independent components are identified in the fluorescence signal that show a different dynamics with varying excitation intensity, and which can be respectively modeled as a bimolecular and unimolecolar process. An interpretation of the observed recombination kinetics in terms of interacting electron and hole polarons is proposed.