Abstract
Linear in the wave-vector terms of an electron Hamiltonian play an important role in topological insulators and spintronic devices. Here we demonstrate how an external electric field controls the magnitude of a linear-in-K term in the exciton Hamiltonian in wide GaAs quantum wells. The dependence of this term on the applied field in a high quality sample was studied by means of the differential reflection spectroscopy. An excellent agreement between the experimental data and the results of calculations using semi-classical non-local dielectric response model confirms the validity of the method and paves the way for the realisation of excitonic Datta-and-Das transistors. In full analogy with the spin-orbit transistor proposed by Datta and Das [Appl. Phys. Lett. {\bf 56}, 665 (1990)], the switch between positive and negative interference of exciton polaritons propagating forward and backward in a GaAs film is achieved by application of an electric field with non-zero component in the plane of the quantum well layer.
Highlights
GaAs is the best studied direct band-gap semiconductor nowadays
We have found that varying the magnitude of the linear-in-K terms by tuning the external electric field, one should be able to invert the shape of excitonic resonances in the reflectivity spectra
The experimental study of electroreflectance spectra of a semiconductor structure containing a wide GaAs quantum wells (QWs) in the presence of an electric field applied at some angle to the growth axis has revealed a new effect
Summary
GaAs is the best studied direct band-gap semiconductor nowadays. A remarkable progress of the epitaxial growth technology made it possible to fabricate nearly ideal layers of GaAs, where very fine quantum effects may be studied. Coupling in semiconductors are extensively studied [2,5,15,16], less is known about spin-independent linear-in-k terms that may be induced by strain or external electric field. The states are typically observed as resonant features (oscillations) in the reflectance spectra of the heterostructures [40,41,42,43,44,45,46,47,48,49,50,51] This allows one to study the effects of the external fields on the propagating excitons. In this work we study the quantum-confined exciton states in a wide QW in the presence of an electric field, which contains a nonzero in-plane component.
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