title: Atomically Precise Lateral Modulation of a Two-Dimensional Electron Liquid in Anatase TiO2Thin Films.
abstract: Engineering the electronic band structure of two-dimensional electron liquids (2DELs) confined at the surface or interface of transition metal oxides is key to unlocking their full potential. Here we describe a new approach to tailoring the electronic structure of an oxide surface 2DEL demonstrating the lateral modulation of electronic states with atomic scale precision on an unprecedented length scale comparable to the Fermi wavelength. To this end, we use pulsed laser deposition to grow anatase TiO2films terminated by a (1 × 4) in-plane surface reconstruction. Employing photostimulated chemical surface doping we induce 2DELs with tunable carrier densities that are confined within a few TiO2layers below the surface. Subsequent in situ angle-resolved photoemission experiments demonstrate that the (1 × 4) surface reconstruction provides a periodic lateral perturbation of the electron liquid. This causes strong backfolding of the electronic bands, opening of unidirectional gaps and a saddle point singularity in the density of states near the chemical potential.
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.|Department of Quantum Matter Physics, University of Geneva , 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: Z
authors.identifier: 0000-0002-4854-2170
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institut für Theoretische Physik und Astrophysik, Universität Würzburg , Am Hubland, Würzburg 97070 Germany.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Department of Quantum Matter Physics, University of Geneva , 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: McKeown Walker
authors.affiliation: Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Ristic
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: J-Z
authors.initials: JZ
authors.lastname: Ma
authors.affiliation: Department of Quantum Matter Physics, University of Geneva , 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: F Y
authors.identifier: 0000-0002-3970-8837
authors.initials: FY
authors.lastname: Bruno
authors.affiliation: Department of Quantum Matter Physics, University of Geneva , 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Riccò
authors.affiliation: Institut für Theoretische Physik und Astrophysik, Universität Würzburg , Am Hubland, Würzburg 97070 Germany.
authors.forename: G
authors.initials: G
authors.lastname: Sangiovanni
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: G
authors.initials: G
authors.lastname: Eres
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.
authors.forename: N C
authors.initials: NC
authors.lastname: Plumb
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.|SwissFEL, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Patthey
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Shi
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.|Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.|Laboratory for Solid State Physics, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Mesot
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.|Department of Quantum Matter Physics, University of Geneva , 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Baumberger
authors.affiliation: Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.|SwissFEL, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Radovic
keywords: Titanium dioxide; angle-resolved photoemission spectroscopy; lateral patterning; surface reconstruction; two-dimensional electron liquid