Electron transport through double quantum dots

TLDR

Electron transport through series‑coupled lateral quantum dots is reviewed, emphasizing the charge stability diagram and resonant tunneling that enable precise measurement of discrete state lifetimes. The review aims to explore double quantum dot studies as a pathway to solid‑state quantum bits. The study examines how discrete energy levels evolve under magnetic fields. High‑resolution measurements reveal avoided crossings and, via microwave spectroscopy, the transition from ionic to covalent bonding as interdot coupling increases.

Abstract

Electron transport experiments on two lateral quantum dots coupled in series are reviewed. An introduction to the charge stability diagram is given in terms of the electrochemical potentials of both dots. Resonant tunneling experiments show that the double dot geometry allows for an accurate determination of the intrinsic lifetime of discrete energy states in quantum dots. The evolution of discrete energy levels in magnetic field is studied. The resolution allows one to resolve avoided crossings in the spectrum of a quantum dot. With microwave spectroscopy it is possible to probe the transition from ionic bonding (for weak interdot tunnel coupling) to covalent bonding (for strong interdot tunnel coupling) in a double dot artificial molecule. This review is motivated by the relevance of double quantum dot studies for realizing solid state quantum bits.