Excitons in quantum technologies: The role of strain engineering

Abstract

As quantum communication channels, single photons render an excellent platform, which is why they are called flying qubits. They are easily transported over long distances via fibers or even satellites due to their remarkably weak interaction with each other. Therefore, some sort of link between photons is required to carry out quantum operations. Ideally, this process is carried out on a robust solid-state chip infrastructure. In this context, excitons (i.e., bound electron–hole pairs in semiconductors) are an ideal connection between photons and the solid state. Due to their mostly strong dipole character, excitons can be efficiently created by photons and inversely create photons upon recombination. This makes excitons in various semiconductor platforms key players in modern quantum technology approaches. While in extended crystal systems, excitons can be transported, their confinement to quasi-0D is used to create stationary solid-state qubits. In addition, excitons provide interactions with other degrees of freedom that can be harnessed in quantum technologies (i.e., spin or mechanical excitations of the host crystal lattice). Here, we review different approaches that use static or dynamic strain to tailor the optical properties of excitons or provide transport channels for excitons. We highlight approaches in traditional bulk semiconductor platforms and modern van der Waals semiconductors.Graphical abstract