title: Giant conductivity switching of LaAlO3/SrTiO3 heterointerfaces governed by surface protonation.
abstract: Complex-oxide interfaces host a diversity of phenomena not present in traditional semiconductor heterostructures. Despite intense interest, many basic questions remain about the mechanisms that give rise to interfacial conductivity and the role of surface chemistry in dictating these properties. Here we demonstrate a fully reversible >4 order of magnitude conductance change at LaAlO3/SrTiO3 (LAO/STO) interfaces, regulated by LAO surface protonation. Nominally conductive interfaces are rendered insulating by solvent immersion, which deprotonates the hydroxylated LAO surface; interface conductivity is restored by exposure to light, which induces reprotonation via photocatalytic oxidation of adsorbed water. The proposed mechanisms are supported by a coordinated series of electrical measurements, optical/solvent exposures, and X-ray photoelectron spectroscopy. This intimate connection between LAO surface chemistry and LAO/STO interface physics bears far-reaching implications for reconfigurable oxide nanoelectronics and raises the possibility of novel applications in which electronic properties of these materials can be locally tuned using synthetic chemistry.
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Keith A
authors: KA
authors: Brown
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Shu
authors: S
authors: He
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Daniel J
authors: DJ
authors: Eichelsdoerfer
authors: Department of Physics and Astronomy, University of Pittsburgh, 100 Allen Hall, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15260, USA.|Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA.
authors: Mengchen
authors: M
authors: Huang
authors: Department of Physics and Astronomy, University of Pittsburgh, 100 Allen Hall, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15260, USA.|Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA.
authors: Ishan
authors: I
authors: Levy
authors: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors: Hyungwoo
authors: H
authors: Lee
authors: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors: Sangwoo
authors: S
authors: Ryu
authors: Department of Physics and Astronomy, University of Pittsburgh, 100 Allen Hall, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15260, USA.|Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA.
authors: Patrick
authors: P
authors: Irvin
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Jose
authors: J
authors: Mendez-Arroyo
authors: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors: Chang-Beom
authors: CB
authors: Eom
authors: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Chad A
authors: CA
authors: Mirkin
authors: Department of Physics and Astronomy, University of Pittsburgh, 100 Allen Hall, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15260, USA.|Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA.
authors: Jeremy
authors: J
authors: Levy