Anisotropic two-dimensional electron gas at SrTiO3(110)

Zhiming Wang; Zhicheng Zhong; Xianfeng Hao; Stefan Gerhold; Bernhard Stoeger; Michael Schmid; Jaime Sanchez-Barriga; Andrei Varykhalov; Cesare Franchini; Karsten Held; Ulrike Diebold

doi:10.1073/pnas.1318304111

Anisotropic two-dimensional electron gas at SrTiO3(110)

Zhiming Wang
, Zhicheng Zhong
, Xianfeng Hao
, Stefan Gerhold
, Bernhard Stoeger
, Michael Schmid
, Jaime Sanchez-Barriga
, Andrei Varykhalov
, Cesare Franchini
, Karsten Held
, Ulrike Diebold (Corresponding author)

Computational Materials Physics

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

Two-dimensional electron gases (2DEGs) at oxide heterostructures are attracting considerable attention, as these might one day substitute conventional semiconductors at least for some functionalities. Here we present a minimal setup for such a 2DEG-the SrTiO3(110)-(4 x 1) surface, natively terminated with one monolayer of tetrahedrally coordinated titania. Oxygen vacancies induced by synchrotron radiation migrate underneath this overlayer; this leads to a confining potential and electron doping such that a 2DEG develops. Our angle-resolved photoemission spectroscopy and theoretical results show that confinement along (110) is strikingly different from the (001) crystal orientation. In particular, the quantized subbands show a surprising "semiheavy" band, in contrast with the analog in the bulk, and a high electronic anisotropy. This anisotropy and even the effective mass of the (110) 2DEG is tunable by doping, offering a high flexibility to engineer the properties of this system.

Original language	English
Pages (from-to)	3933-3937
Number of pages	5
Journal	Proceedings of the National Academy of Sciences of the United States of America (PNAS)
Volume	111
Issue number	11
DOIs	https://doi.org/10.1073/pnas.1318304111
Publication status	Published - 18 Mar 2014

Funding

Z.W., X.H., and U.D. gratefully acknowledge support by the European Research Council (ERC) Advanced Grant "OxideSurfaces" and the Austrian Science Fund (Fonds zur Forderung der Wissenschaftlichen Forschung, FWF, Project F45). Z.Z. acknowledges support by the FWF through SFB VicOM F41. K.H. acknowledges support by the ERC Starting Grant AbinitioDFA, Grant Agreement 306447. The DFT computations were performed on the Vienna Scientific Cluster (VSC-2).

Austrian Fields of Science 2012

103025 Quantum mechanics
103036 Theoretical physics
103015 Condensed matter
103009 Solid state physics

Keywords

oxide surface
electronic structure
quantum confinement
perovskite
ARPES
LOCALIZED WANNIER FUNCTIONS
MOLECULAR-DYNAMICS
SURFACE
OXIDE
INTERFACES
METALS
STATES
Quantum confinement
Oxide surface
Perovskite
Electronic structure

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10.1073/pnas.1318304111

http://arxiv.org/abs/1309.7042

Cite this

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title = "Anisotropic two-dimensional electron gas at SrTiO3(110)",

abstract = "Two-dimensional electron gases (2DEGs) at oxide heterostructures are attracting considerable attention, as these might one day substitute conventional semiconductors at least for some functionalities. Here we present a minimal setup for such a 2DEG-the SrTiO3(110)-(4 x 1) surface, natively terminated with one monolayer of tetrahedrally coordinated titania. Oxygen vacancies induced by synchrotron radiation migrate underneath this overlayer; this leads to a confining potential and electron doping such that a 2DEG develops. Our angle-resolved photoemission spectroscopy and theoretical results show that confinement along (110) is strikingly different from the (001) crystal orientation. In particular, the quantized subbands show a surprising {"}semiheavy{"} band, in contrast with the analog in the bulk, and a high electronic anisotropy. This anisotropy and even the effective mass of the (110) 2DEG is tunable by doping, offering a high flexibility to engineer the properties of this system.",

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author = "Zhiming Wang and Zhicheng Zhong and Xianfeng Hao and Stefan Gerhold and Bernhard Stoeger and Michael Schmid and Jaime Sanchez-Barriga and Andrei Varykhalov and Cesare Franchini and Karsten Held and Ulrike Diebold",

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T1 - Anisotropic two-dimensional electron gas at SrTiO3(110)

AU - Wang, Zhiming

AU - Zhong, Zhicheng

AU - Hao, Xianfeng

AU - Gerhold, Stefan

AU - Stoeger, Bernhard

AU - Schmid, Michael

AU - Sanchez-Barriga, Jaime

AU - Varykhalov, Andrei

AU - Franchini, Cesare

AU - Held, Karsten

AU - Diebold, Ulrike

PY - 2014/3/18

Y1 - 2014/3/18

N2 - Two-dimensional electron gases (2DEGs) at oxide heterostructures are attracting considerable attention, as these might one day substitute conventional semiconductors at least for some functionalities. Here we present a minimal setup for such a 2DEG-the SrTiO3(110)-(4 x 1) surface, natively terminated with one monolayer of tetrahedrally coordinated titania. Oxygen vacancies induced by synchrotron radiation migrate underneath this overlayer; this leads to a confining potential and electron doping such that a 2DEG develops. Our angle-resolved photoemission spectroscopy and theoretical results show that confinement along (110) is strikingly different from the (001) crystal orientation. In particular, the quantized subbands show a surprising "semiheavy" band, in contrast with the analog in the bulk, and a high electronic anisotropy. This anisotropy and even the effective mass of the (110) 2DEG is tunable by doping, offering a high flexibility to engineer the properties of this system.

AB - Two-dimensional electron gases (2DEGs) at oxide heterostructures are attracting considerable attention, as these might one day substitute conventional semiconductors at least for some functionalities. Here we present a minimal setup for such a 2DEG-the SrTiO3(110)-(4 x 1) surface, natively terminated with one monolayer of tetrahedrally coordinated titania. Oxygen vacancies induced by synchrotron radiation migrate underneath this overlayer; this leads to a confining potential and electron doping such that a 2DEG develops. Our angle-resolved photoemission spectroscopy and theoretical results show that confinement along (110) is strikingly different from the (001) crystal orientation. In particular, the quantized subbands show a surprising "semiheavy" band, in contrast with the analog in the bulk, and a high electronic anisotropy. This anisotropy and even the effective mass of the (110) 2DEG is tunable by doping, offering a high flexibility to engineer the properties of this system.

KW - oxide surface

KW - electronic structure

KW - quantum confinement

KW - perovskite

KW - ARPES

KW - LOCALIZED WANNIER FUNCTIONS

KW - MOLECULAR-DYNAMICS

KW - SURFACE

KW - OXIDE

KW - INTERFACES

KW - METALS

KW - STATES

KW - Quantum confinement

KW - Oxide surface

KW - Perovskite

KW - Electronic structure

UR - https://www.scopus.com/pages/publications/84896529352

U2 - 10.1073/pnas.1318304111

DO - 10.1073/pnas.1318304111

M3 - Article

SN - 0027-8424

VL - 111

SP - 3933

EP - 3937

JO - Proceedings of the National Academy of Sciences of the United States of America (PNAS)

JF - Proceedings of the National Academy of Sciences of the United States of America (PNAS)

IS - 11

ER -

Anisotropic two-dimensional electron gas at SrTiO3(110)

Abstract

Funding

Austrian Fields of Science 2012

Keywords

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