Valley Polarized Single Photon Source Based on Transition Metal Dichalcogenides Quantum Dots

Abstract

Photonic quantum computer, quantum communication, quantum metrology, and optical quantum information processing require a development of efficient solid-state single photon sources. However, it still remains a challenge. We report theoretical framework and experimental development on a novel kind of valley-polarized single-photon emitter (SPE) based on two-dimensional transition metal dichalcogenides (TMDCs) quantum dots. In order to reveal the principle of the SPE, we make a brief review on the electronic structure of the TMDCs and excitonic behavior in photoluminescence (PL) and in magneto-PL of these materials. We also discuss coupled spin and valley physics, valleypolarized optical absorption, and magneto-optical absorption in TMDC quantum dots. We demonstrate that the valley-polarization is robust against dot size and magnetic field, but optical transition energies show sizable size-effect. Three versatile models, including density functional theory, tight-binding and effective k Á p method, have been adopted in our calculations and the corresponding results have been presented.