title: Observation of surface Dirac cone in high-quality ultrathin epitaxial Bi2Se3 topological insulator on AlN(0001) dielectric.
abstract: Bi2Se3 topological insulators (TIs) are grown on AlN(0001)/Si(111) substrates by molecular beam epitaxy. In a one-step growth at optimum temperature of 300 °C, Bi2Se3 bonds strongly with AlN without forming interfacial reaction layers. This produces high epitaxial quality Bi2Se3 single crystals with a perfect registry with the substrate and abrupt interfaces, allowing thickness scaling down to three quintuple layers (QL) without jeopardizing film quality. It is found by angle-resolved photoelectron spectroscopy that, remarkably, Bi2Se3 films maintain the 3D TI properties at very low thickness of 3QL (∼2.88 nm), exhibiting top surface gapless metallic states in the form of a Dirac cone.
authors.affiliation: National Center for Scientific Research, DEMOKRITOS , 15310 Athens, Greece.
authors.forename: Polychronis
authors.initials: P
authors.lastname: Tsipas
authors.forename: Evangelia
authors.initials: E
authors.lastname: Xenogiannopoulou
authors.forename: Spyridon
authors.initials: S
authors.lastname: Kassavetis
authors.forename: Dimitra
authors.initials: D
authors.lastname: Tsoutsou
authors.forename: Evangelos
authors.initials: E
authors.lastname: Golias
authors.forename: Calliope
authors.initials: C
authors.lastname: Bazioti
authors.forename: George P
authors.initials: GP
authors.lastname: Dimitrakopulos
authors.forename: Philomela
authors.initials: P
authors.lastname: Komninou
authors.forename: Hu
authors.initials: H
authors.lastname: Liang
authors.forename: Matty
authors.initials: M
authors.lastname: Caymax
authors.forename: Athanasios
authors.initials: A
authors.lastname: Dimoulas