Topological insulator quantum dot with tunable barriers

TL;DR

This paper demonstrates tunable barrier quantum dots in topological insulators, showing Coulomb blockade and excited states, with potential for quantum device applications.

Contribution

It introduces a method to create topological insulator quantum dots with tunable barriers using ultrathin Bi2Se3 regions, enabling control over conduction regimes.

Findings

Coulomb blockade observed with >5 meV charging energy

Barriers tunable from Ohmic to tunneling via gate voltage

Presence of excited states in transport spectroscopy

Abstract

Thin (6-7 quintuple layer) topological insulator Bi2Se3 quantum dot devices are demonstrated using ultrathin (2~4 quintuple layer) Bi2Se3 regions to realize semiconducting barriers which may be tuned from Ohmic to tunneling conduction via gate voltage. Transport spectroscopy shows Coulomb blockade with large charging energy >5 meV, with additional features implying excited states.