Coherent electronic Raman excitation of valley-orbit split states of phosphorus dopants in silicon

TL;DR

This paper demonstrates coherent optical Raman excitation of phosphorus donor states in silicon, revealing how carrier density influences wavepacket dynamics and enabling access to otherwise forbidden transitions.

Contribution

It introduces a method for coherent optical excitation of phosphorus dopant states in silicon and explores the transition from Raman to impulsive excitation regimes.

Findings

Wavepacket dynamics depend on pre-excited carrier density.

Raman excitation can be converted to impulsive excitation under certain conditions.

Access to Raman-forbidden transitions is achieved.

Abstract

In this study, we demonstrate coherent optical excitation of the electronic Raman transition between the $1s\left(A_1\right)$ and $1s\left(E\right)$ split states of phosphorus donor in crystalline silicon. The dynamics of the generated wavepacket is characterized in the time domain using a degenerate pump-probe technique with mid-infrared femtosecond pulses via transient polarization anisotropy of the probe pulse. In addition, we study the role of resonantly excited carriers, and we show that the amplitude and coherence time of the electronic wavepacket depend on the pre-excited carrier density. Further, we demonstrate that under certain conditions, the Raman-type excitation changes to displacive impulsive excitation, which allows us to address the Raman-forbidden transition between $1s\left(A_1\right)$ and $1s\left(T_1\right)$.