Topological Insulator Quantum Dot with Tunable Barriers

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 and additional features implying excited states.