Hybrid metal-semiconductor quantum dots in InAs as a platform for quantum simulation

Abstract

Arrays of hybrid metal-semiconductor islands offer a new approach to quantum simulation, with key advantages over arrays of conventional quantum dots. Because the metallic component of these hybrid islands has a quasi-continuous level spectrum, each site in an array can be effectively electronically identical; in contrast, each conventional semiconductor quantum dot has its own spectral fingerprint. Meanwhile, the semiconductor component retains gate-tunability of intersite coupling. This combination creates a scalable platform for simulating correlated ground states driven by Coulomb interactions. We report the fabrication and characterization of hybrid metal-semiconductor islands, featuring a submicron metallic component transparently contacting a gate-confined region of an InAs quantum well with tunable couplings to macroscopic leads. Tuning to the weak-coupling limit forms a single-electron transistor with highly-uniform Coulomb peaks, with no resolvable excitation spectrum in the Coulomb diamonds. Upon increasing the transmissions toward the ballistic regime we observe an evolution to dynamical Coulomb blockade.