Control of a two-dimensional electron gas on SrTiO₃(111) by atomic oxygen.
We report on the formation of a two-dimensional electron gas (2DEG) at the bare surface of (111) oriented SrTiO3. Angle resolved photoemission experiments reveal highly itinerant carriers with a sixfold symmetric Fermi surface and strongly anisotropic effective masses. The electronic structure of the 2DEG is in good agreement with self-consistent tight-binding supercell calculations that incorporate a confinement potential due to surface band bending. We further demonstrate that alternate exposure of the surface to ultraviolet light and atomic oxygen allows tuning of the carrier density and the complete suppression of the 2DEG.
Département de Physique de la Matière Condensée, Universitée de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
S McKeown
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Walker
Département de Physique de la Matière Condensée, Universitée de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
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de la Torre
Département de Physique de la Matière Condensée, Universitée de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
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Bruno
Département de Physique de la Matière Condensée, Universitée de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
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Tamai
Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom.
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Kim
Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom.
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Hoesch
Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
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Shi
Quantum-Phase Electronics Center, Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan and RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
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Bahramy
SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, United Kingdom.
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King
Département de Physique de la Matière Condensée, Universitée de Genève, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, United Kingdom.
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Baumberger