title: Realization of a vertical topological p-n junction in epitaxial Sb2Te3/Bi2Te3 heterostructures.
abstract: Three-dimensional (3D) topological insulators are a new state of quantum matter, which exhibits both a bulk band structure with an insulating energy gap as well as metallic spin-polarized Dirac fermion states when interfaced with a topologically trivial material. There have been various attempts to tune the Dirac point to a desired energetic position for exploring its unusual quantum properties. Here we show a direct experimental proof by angle-resolved photoemission of the realization of a vertical topological p-n junction made of a heterostructure of two different binary 3D TI materials Bi2Te3 and Sb2Te3 epitaxially grown on Si(111). We demonstrate that the chemical potential is tunable by about 200 meV when decreasing the upper Sb2Te3 layer thickness from 25 to 6 quintuple layers without applying any external bias. These results make it realistic to observe the topological exciton condensate and pave the way for exploring other exotic quantum phenomena in the near future.
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Eschbach
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.|Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Młyńczak
authors.affiliation: RWTH Aachen University, II Institute of Physics B and JARA-FIT, 52074 Aachen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kellner
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Kampmeier
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Lanius
authors.affiliation: Forschungszentrum Jülich GmbH, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, 52425 Jülich, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Neumann
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weyrich
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Gehlmann
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Pika
authors.initials: P
authors.lastname: Gospodarič
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Döring
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Mussler
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-2) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Demarina
authors.affiliation: Forschungszentrum Jülich GmbH, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, 52425 Jülich, Germany.|Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-5) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Luysberg
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-1) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Gustav
authors.identifier: http://orcid.org/0000-0002-6615-1122
authors.initials: G
authors.lastname: Bihlmayer
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schäpers
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Plucinski
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-1) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Blügel
authors.affiliation: RWTH Aachen University, II Institute of Physics B and JARA-FIT, 52074 Aachen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Morgenstern
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-6) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Claus M
authors.initials: CM
authors.lastname: Schneider
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-9) and JARA-FIT, 52425 Jülich, Germany.
authors.forename: Detlev
authors.initials: D
authors.lastname: Grützmacher