title: A high-mobility electronic system at an electrolyte-gated oxide surface.
abstract: Electrolyte gating is a powerful technique for accumulating large carrier densities at a surface. Yet this approach suffers from significant sources of disorder: electrochemical reactions can damage or alter the sample, and the ions of the electrolyte and various dissolved contaminants sit Angstroms from the electron system. Accordingly, electrolyte gating is well suited to studies of superconductivity and other phenomena robust to disorder, but of limited use when reactions or disorder must be avoided. Here we demonstrate that these limitations can be overcome by protecting the sample with a chemically inert, atomically smooth sheet of hexagonal boron nitride. We illustrate our technique with electrolyte-gated strontium titanate, whose mobility when protected with boron nitride improves more than 10-fold while achieving carrier densities nearing 10(14) cm(-2). Our technique is portable to other materials, and should enable future studies where high carrier density modulation is required but electrochemical reactions and surface disorder must be minimized.
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Gallagher
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Menyoung
authors.identifier: 0000000319543198
authors.initials: M
authors.lastname: Lee
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Petach
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Sam W
authors.initials: SW
authors.lastname: Stanwyck
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Williams
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Kenji
authors.identifier: 0000000337018119
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: David
authors.initials: D
authors.lastname: Goldhaber-Gordon