The Rashba effect in Ge/Si0.15Ge0.85 multiple quantum wells embedded in a p-i-n diode is studied through polarization and time-resolved photoluminescence. In addition to a sizeable redshift arising from the quantum-confined Stark effect, a threefold enhancement of the circular polarization degree of the direct transition is obtained by increasing the pump power over a 2kW/cm2 range. This marked variation reflects an efficient modulation of the spin population and is further supported by dedicated investigations of the indirect gap transition. This study demonstrates a viable strategy to engineer the spin-orbit Hamiltonian through contactless optical excitation and opens the way towards the electro-optical manipulation of spins in quantum devices based on group-IV heterostructures.
@article{arxiv.2205.10134,
title = {Optical manipulation of the Rashba effect in germanium quantum wells},
author = {S. Rossi and E. Talamas Simola and M. Raimondo and M. Acciarri and J. Pedrini and A. Balocchi and X. Marie and G. Isella and F. Pezzoli},
journal= {arXiv preprint arXiv:2205.10134},
year = {2022}
}