Material Platforms for Quantum Emitters and Qubits
The ideal quantum emitter material platform would have an ordered array of deterministically-positioned perfectly-identical sources emitting single photons at the desired wavelength at room temperature. The ideal material platform for quantum bits (qubits) controlled by light would similarly be an ordered array of perfectly-identical sites in which interactions with light control a longer-lived state such as the spin projection of a single electron bound to the site. In such a case the spin projection of the electron could serve as the qubit, with initialization, manipulation, and readout all controlled by optical pulses incident on the qubit. A wide variety of optically-active materials have been explored as potential platforms for Quantum Emitters or Qubits, but realistic materials can never achieve the ideal conditions. For example, low levels of impurities or defects can cause each site to have random fluctuations in photon energy, surfaces usually induce nonradiative relaxation that limits performance, and low temperatures are often needed to keep carriers confined to the localized sites that define the emitter or qubit.
At UD we are exploring and engineering a number of material platforms for quantum emitter and qubit applications. They include heterostructures containing III-V quantum dots, two-dimensional materials such as III-VI and Transition Metal Dichalcogenides, and Nitrogen Vacancy Centers in Diamond. Our research typically considers methods for growing materials with optimized properties, methods for templating emitter or qubit sites, fabrication of devices to control applied electric and magnetic fields, optical characterization and control of materials, and theory to understand the origins and fluctuations of state energies.
Participating Faculty: Doty, Chakraborty, Law, Ku, Zide, Janotti, Hossain