Optical manipulation of the Rashba effect in germanium quantum wells

Abstract

The Rashba effect in Ge/Si${}_{0.15}$Ge${}_{0.85}$ 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/cm${}^2$ 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.

References in corpus (3)

• Cubic Rashba spin-orbit interaction of two-dimensional hole gas in strained-Ge/SiGe quantum well
• Intrinsic Spin Lifetime of Conduction Electrons in Germanium
• g-Factor Tuning and Manipulation of Spins by an Electric Current