title: Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces by charge-transfer-induced modulation doping.
abstract: Two-dimensional electron gases (2DEGs) formed at the interface of insulating complex oxides promise the development of all-oxide electronic devices. These 2DEGs involve many-body interactions that give rise to a variety of physical phenomena such as superconductivity, magnetism, tunable metal-insulator transitions and phase separation. Increasing the mobility of the 2DEG, however, remains a major challenge. Here, we show that the electron mobility is enhanced by more than two orders of magnitude by inserting a single-unit-cell insulating layer of polar La(1-x)Sr(x)MnO3 (x = 0, 1/8, and 1/3) at the interface between disordered LaAlO3 and crystalline SrTiO3 produced at room temperature. Resonant X-ray spectroscopy and transmission electron microscopy show that the manganite layer undergoes unambiguous electronic reconstruction, leading to modulation doping of such atomically engineered complex oxide heterointerfaces. At low temperatures, the modulation-doped 2DEG exhibits Shubnikov-de Haas oscillations and fingerprints of the quantum Hall effect, demonstrating unprecedented high mobility and low electron density.
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Chen
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark.
authors.forename: F
authors.initials: F
authors.lastname: Trier
authors.affiliation: Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Wijnands
authors.affiliation: 1] Quantum Matter Institute, Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada [2] Max Planck Institute for Chemical Physics of Solids, Nöthnitzerstraße 40, 01187 Dresden, Germany.
authors.forename: R J
authors.initials: RJ
authors.lastname: Green
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 2020 Antwerp, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Gauquelin
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 2020 Antwerp, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Egoavil
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark.
authors.forename: D V
authors.initials: DV
authors.lastname: Christensen
authors.affiliation: Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Koster
authors.affiliation: Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Huijben
authors.affiliation: Nano-Science Center, Department of Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Bovet
authors.affiliation: 1] Quantum Matter Institute, Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada [2] Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Macke
authors.affiliation: Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada.
authors.forename: F
authors.initials: F
authors.lastname: He
authors.affiliation: Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Sutarto
authors.affiliation: Department of Physics, Technical University of Denmark, 2800 Lyngby, Denmark.
authors.forename: N H
authors.initials: NH
authors.lastname: Andersen
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: J A
authors.initials: JA
authors.lastname: Sulpizio
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Honig
authors.affiliation: Center for Quantum devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
authors.forename: G E D K
authors.initials: GE
authors.lastname: Prawiroatmodjo
authors.affiliation: Center for Quantum devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
authors.forename: T S
authors.initials: TS
authors.lastname: Jespersen
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Linderoth
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Ilani
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 2020 Antwerp, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Verbeeck
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 2020 Antwerp, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Van Tendeloo
authors.affiliation: Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Rijnders
authors.affiliation: Quantum Matter Institute, Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: G A
authors.initials: GA
authors.lastname: Sawatzky
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Pryds