Probing a single quantum dot by pulsed and continuous microwave radiation

Abstract

Using both picosecond millimeter-wave impulses and continuous microwave radiation, we probe the electronic structure and dynamic response of single-electron tunneling in structured quantum dots, essential for understanding their applications as computational elements, emitters and detectors. Under pulsed microwave radiation, the dot's capacitance is greatly reduced compared to the equilibrium values. In contrast, the dot's capacitance remains constant under continuous microwave radiation. This phenomenological reduction of capacitance stems from the faster pumping of electrons by pulsed microwave excitation as compared to the slow relaxation of electrons.