Single Exciton Transistor based on van der Waals Heterostructures

The spin degree of freedom of an electron captures the essence of quantum mechanics.

Via a phenomenon called Coulomb blockade, electrons can be loaded one-by-one into a microscopic device, and their spin can be probed by electrical or optical readouts, satisfying some criteria to construct a quantum processor.Unfortunately, electrons interact indirectly with light (photons), essential for ultra-fast coherent control and to communicate the quantum information over long distances.

Conversely, an exciton – a quasiparticle consisting of a strongly bound electron-hole pair in a semiconductor – interacts with light very strongly.

With the emergence of atomically thin semiconductors which have exciton binding energies and Coulomb interactions ~ 100x larger than traditional semiconductors such as GaAs, it is possible to engineer a single exciton transistor. In this fellowship, I propose to pursue excitonic transport and controlled electrostatic trapping of single excitons.

To realize such devices, I will stack atom-thick flakes together to form 2D heterostructures which allow separation of the electron and hole into different layers, creating an interlayer exciton which has a long lifetime, a large permanent dipole, and convenient energy scales.

The interlayer excitons can strongly interact with each other, providing the repulsion energy to realize excitonic Coulomb blockade.

Success in this endeavor opens a path to realizing novel sources of single photons, entangled photons, and efficient spin-photon interfaces.

This Fellowship will offer me the opportunity to acquire new skills regarding magneto-optical spectroscopy, quantum optics, transport device design and fabrication. It builds on my PhD project, where I focused on intralayer excitons in 2D materials and heterostructure fabrication.

This project exploits my strong background in material/device preparation and marries it with quantum optics, which is the expertise of host group.