Vyacheslavs Kashcheyevs Abstract

"Electrons on demand from dynamic quantum dots: how to be fast but precise"

SPEAKER: Dr. Vyacheslavs Kashcheyevs, University of Latvia (Riga, Latvia)

ABSTRACT: Dynamic quantum dots are artificial atoms created electrostatically within a two-dimensional electron gas confined between two epitaxially-matched semiconductors. Tunneling barriers tuned by submicron gates allow for rapid change of coupling between the discrete levels of confined electron and the electron-hole continuum in the leads. My talk will center on universal aspects of a simple device design called single-parameter non-adiabatic electron pump. Such a pump takes a well-defined number of electrons from the source and ejects them into the drain at specific energy with high (several gigaherz) repetition rate. Experimental data from Physikalisch-Technische Bundesanstalt (PTB in Braunschweig, Germany) will be contrasted with a simple rate-equations theory that reveals analogy to decay cascades in nuclear physics and potentially allows for controlled initialization of specific quantum states. Present status of these devices with respect to the metrological goal of an electron-charge based standard for electrical current will also be discussed.