Direct observation of a two-dimensional hole gas at oxide interfaces

doi:10.1038/s41563-017-0002-4

Title: Direct observation of a two-dimensional hole gas at oxide interfaces

Abstract

The discovery of a two-dimensional electron gas (2DEG) at the LaAlO ₃/SrTiO ₃ interface has resulted in the observation of many properties not present in conventional semiconductor heterostructures, and so become a focal point for device applications. Its counterpart, the two-dimensional hole gas (2DHG), is expected to complement the 2DEG. However, although the 2DEG has been widely observed, the 2DHG has proved elusive. Here in this paper we demonstrate a highly mobile 2DHG in epitaxially grown SrTiO ₃/LaAlO ₃/SrTiO ₃ heterostructures. Using electrical transport measurements and in-line electron holography, we provide direct evidence of a 2DHG that coexists with a 2DEG at complementary heterointerfaces in the same structure. First-principles calculations, coherent Bragg rod analysis and depth-resolved cathodoluminescence spectroscopy consistently support our finding that to eliminate ionic point defects is key to realizing a 2DHG. Lastly, the coexistence of a 2DEG and a 2DHG in a single oxide heterostructure provides a platform for the exciting physics of confined electron-hole systems and for developing applications.

Authors:

Lee, H. ^[1]; Campbell, N. ^[2]; Lee, J. ^[3]; Asel, T. J. ^[4]; Paudel, T. R. ^[5]; Zhou, H. ^[6]; Lee, J. W. ^[1]; Noesges, B. ^[4]; Seo, J. ^[3];

^[7]; Brillson, L. J. ^[8]; Oh, S. H. ^[3]; Tsymbal, E. Y. ^[5]; Rzchowski, M. S. ^[2]; Eom, C. B. ^[1]

Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics
Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Energy Science
The Ohio State Univ., Columbus, OH (United States). Dept. of Physics
Univ. of Nebraska, Lincoln, NE (United States). Nebraska Center for Materials and Nanoscience, Dept. of Physics and Astronomy
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS), X-Ray Science Division
Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Energy Science; Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of). Dept. of Materials Science and Engineering
The Ohio State Univ., Columbus, OH (United States). Dept. of Physics; The Ohio State Univ., Columbus, OH (United States). Dept. of Electrical and Computer Engineering

Publication Date:: 2018-02-05

Research Org.:: Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

OSTI Identifier:: 1469800

Grant/Contract Number:: AC02-06CH11357; FG02-06ER46327; DMR-1629270; DMR-1420645; DMR-1305193; FA9550-15-1-0334; FA2386-15-1-4046

Resource Type:: Accepted Manuscript

Journal Name:: Nature Materials

Additional Journal Information:: Journal Volume: 17; Journal Issue: 3; Journal ID: ISSN 1476-1122

Publisher:: Nature Publishing Group

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE

Citation Formats


                    Lee, H., Campbell, N., Lee, J., Asel, T. J., Paudel, T. R., Zhou, H., Lee, J. W., Noesges, B., Seo, J., Park, B., Brillson, L. J., Oh, S. H., Tsymbal, E. Y., Rzchowski, M. S., and Eom, C. B. Direct observation of a two-dimensional hole gas at oxide interfaces.  United States: N. p., 2018. 
        Web.  doi:10.1038/s41563-017-0002-4.

Copy to clipboard


                    Lee, H., Campbell, N., Lee, J., Asel, T. J., Paudel, T. R., Zhou, H., Lee, J. W., Noesges, B., Seo, J., Park, B., Brillson, L. J., Oh, S. H., Tsymbal, E. Y., Rzchowski, M. S., & Eom, C. B. Direct observation of a two-dimensional hole gas at oxide interfaces.  United States.  doi:10.1038/s41563-017-0002-4.

Copy to clipboard


                    Lee, H., Campbell, N., Lee, J., Asel, T. J., Paudel, T. R., Zhou, H., Lee, J. W., Noesges, B., Seo, J., Park, B., Brillson, L. J., Oh, S. H., Tsymbal, E. Y., Rzchowski, M. S., and Eom, C. B. Mon .  
        "Direct observation of a two-dimensional hole gas at oxide interfaces".  United States.  doi:10.1038/s41563-017-0002-4.  https://www.osti.gov/servlets/purl/1469800.

Copy to clipboard


                    
@article{osti_1469800,

  title        = {Direct observation of a two-dimensional hole gas at oxide interfaces},

  author       = {Lee, H. and Campbell, N. and Lee, J. and Asel, T. J. and Paudel, T. R. and Zhou, H. and Lee, J. W. and Noesges, B. and Seo, J. and Park, B. and Brillson, L. J. and Oh, S. H. and Tsymbal, E. Y. and Rzchowski, M. S. and Eom, C. B.},

  abstractNote = {The discovery of a two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface has resulted in the observation of many properties not present in conventional semiconductor heterostructures, and so become a focal point for device applications. Its counterpart, the two-dimensional hole gas (2DHG), is expected to complement the 2DEG. However, although the 2DEG has been widely observed, the 2DHG has proved elusive. Here in this paper we demonstrate a highly mobile 2DHG in epitaxially grown SrTiO3/LaAlO3/SrTiO3 heterostructures. Using electrical transport measurements and in-line electron holography, we provide direct evidence of a 2DHG that coexists with a 2DEG at complementary heterointerfaces in the same structure. First-principles calculations, coherent Bragg rod analysis and depth-resolved cathodoluminescence spectroscopy consistently support our finding that to eliminate ionic point defects is key to realizing a 2DHG. Lastly, the coexistence of a 2DEG and a 2DHG in a single oxide heterostructure provides a platform for the exciting physics of confined electron-hole systems and for developing applications.},

  doi          = {10.1038/s41563-017-0002-4},

  journal      = {Nature Materials},

  number       = 3,

  volume       = 17,

  place        = {United States},

  year         = {2018},

  month        = {2}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

DOI: 10.1038/s41563-017-0002-4

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 14 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Works referenced in this record:

Magnetic effects at the interface between non-magnetic oxides
journal, June 2007

Brinkman, A.; Huijben, M.; van Zalk, M.
Nature Materials, Vol. 6, Issue 7, p. 493-496
DOI: 10.1038/nmat1931

Projector augmented-wave method
journal, December 1994

Bl�chl, P. E.
Physical Review B, Vol. 50, Issue 24, p. 17953-17979
DOI: 10.1103/PhysRevB.50.17953

Oxide Interfaces--An Opportunity for Electronics
journal, March 2010

Mannhart, J.; Schlom, D. G.
Science, Vol. 327, Issue 5973, p. 1607-1611
DOI: 10.1126/science.1181862

High Mobility in ${LaAlO}_{3} / {SrTiO}_{3}$ Heterostructures: Origin, Dimensionality, and Perspectives
journal, May 2007

Herranz, G.; Basleti?, M.; Bibes, M.
Physical Review Letters, Vol. 98, Issue 21, Article No. 216803
DOI: 10.1103/PhysRevLett.98.216803

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996

Kresse, G.; Furthm�ller, J.
Physical Review B, Vol. 54, Issue 16, p. 11169-11186
DOI: 10.1103/PhysRevB.54.11169

From ultrasoft pseudopotentials to the projector augmented-wave method
journal, January 1999

Kresse, G.; Joubert, D.
Physical Review B, Vol. 59, Issue 3, p. 1758-1775
DOI: 10.1103/PhysRevB.59.1758

Charge localization or itineracy at $La Al O_{3} ? Sr Ti O_{3}$ interfaces Hole polarons, oxygen vacancies, and mobile electrons
journal, July 2006

Pentcheva, R.; Pickett, W. E.
Physical Review B, Vol. 74, Issue 3, Article No. 035112
DOI: 10.1103/PhysRevB.74.035112

Tunable Quasi-Two-Dimensional Electron Gases in Oxide Heterostructures
journal, September 2006

Thiel, S.
Science, Vol. 313, Issue 5795, p. 1942-1945
DOI: 10.1126/science.1131091

Why some interfaces cannot be sharp
journal, January 2006

Nakagawa, Naoyuki; Hwang, Harold Y.; Muller, David A.
Nature Materials, Vol. 5, Issue 3, p. 204-209
DOI: 10.1038/nmat1569

Tunable Rashba Spin-Orbit Interaction at Oxide Interfaces
journal, March 2010

Caviglia, A. D.; Gabay, M.; Gariglio, S.
Physical Review Letters, Vol. 104, Issue 12, Article No. 126803
DOI: 10.1103/PhysRevLett.104.126803

Similar Records in DOE PAGES and OSTI.GOV collections:

Origin of Two-Dimensional Electron Gases at Oxide Interfaces: Insights from Theory

Journal Article Bristowe, N. C. ; Ghosez, Philippe ; Littlewood, Peter B. ; ... - Journal of Physics. Condensed Matter

The response of oxide thin films to polar discontinuities at interfaces and surfaces has generated enormous activity due to the variety of interesting effects that it gives rise to. A case in point is the discovery of the electron gas at the interface between LaAlO3 and SrTiO3, which has since been shown to be quasitwodimensional, switchable, magnetic and/or superconducting. Despite these findings, the origin of the twodimensional electron gas is highly debated and several possible mechanisms remain. Here we review the main proposed mechanisms and attempt to model expected effects in a quantitative way with the ambition of better constrainingmore »« less
Cited by 48
DOI: 10.1088/0953-8984/26/14/143201

Full Text Available
Tunable one-dimensional electron gas carrier densities at nanostructured oxide interfaces

Journal Article Zhang, Lipeng ; Xu, Haixuan ; Kent, Paul R. C. ; ... - Scientific Reports

The emergence of two-dimensional metallic states at the LaAlO ₃/SrTiO ₃ (LAO/STO) heterostructure interface is known to occur at a critical thickness of four LAO over layers. This insulator-to-metal transition can be explained through the polar catastrophe mechanism arising from the divergence of the electrostatic potential at the LAO surface. Here, we demonstrate that nanostructuring can be effective in reducing or eliminating this critical thickness. Employing a modified polar catastrophe" model, we demonstrate that the nanowire heterostructure electrostatic potential diverges more rapidly as a function of layer thickness than in a regular heterostructure. Our first principles calculations indicate that formore »« less
Cited by 1
DOI: 10.1038/srep25452

Full Text Available
LaTiO₃/KTaO₃ interfaces: A new two-dimensional electron gas system

Journal Article Zou, K. ; Ismail-Beigi, Sohrab ; Kisslinger, Kim ; ... - APL Materials

We report a new 2D electron gas (2DEG) system at the interface between a Mott insulator, LaTiO₃, and a band insulator, KTaO₃. For LaTiO₃/KTaO₃ interfaces, we observe metallic conduction from 2 K to 300 K. One serious technological limitation of SrTiO₃-based conducting oxide interfaces for electronics applications is the relatively low carrier mobility (0.5-10 cm²/V s) of SrTiO₃ at room temperature. By using KTaO₃, we achieve mobilities in LaTiO₃/KTaO₃ interfaces as high as 21 cm²/V s at room temperature, over a factor of 3 higher than observed in doped bulk SrTiO₃. By density functional theory, we attribute the higher mobilitymore »« less
Cited by 12
DOI: 10.1063/1.4914310

Full Text Available
Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

Journal Article Kamaraju, N. ; Pan, W. ; Ekenberg, U. ; ... - Applied Physics Letters

Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is also shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also find that impurity scattering dominates cyclotron resonance decay in the 2DHG,more »« less
Cited by 7
DOI: 10.1063/1.4906282

Full Text Available
Magneto-transport analysis of an ultra-low-density two-dimensional hole gas in an undoped strained Ge/SiGe heterostructure

Journal Article Laroche, D. ; Huang, S. -H. ; Chuang, Y. ; ... - Applied Physics Letters

We report the magneto-transport, scattering mechanisms, and e ective mass analysis of an ultralow density two-dimensional hole gas capacitively induced in an undoped strained Ge/Si0:2Ge0:8 heterostructure. This fabrication technique allows hole densities as low as p 1:1 1010 cm² to be achieved, more than one order of magnitude lower than previously reported in doped Ge/SiGe heterostructures. The power-law exponent of the electron mobility versus density curve, / n , is found to be 0:29 over most of the density range, implying that background impurity scattering is the dominant scattering mechanism at intermediate densities in such devices. A charge migration modelmore »« less
Cited by 5
DOI: 10.1063/1.4953399

Full Text Available

Similar Records

Title: Direct observation of a two-dimensional hole gas at oxide interfaces

Abstract

Citation Formats

Magnetic effects at the interface between non-magnetic oxides journal, June 2007

Projector augmented-wave method journal, December 1994

Oxide Interfaces--An Opportunity for Electronics journal, March 2010

High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality, and Perspectives journal, May 2007

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set journal, October 1996

From ultrasoft pseudopotentials to the projector augmented-wave method journal, January 1999

Charge localization or itineracy at LaAlO3?SrTiO3 interfaces Hole polarons, oxygen vacancies, and mobile electrons journal, July 2006

Tunable Quasi-Two-Dimensional Electron Gases in Oxide Heterostructures journal, September 2006

Why some interfaces cannot be sharp journal, January 2006

Tunable Rashba Spin-Orbit Interaction at Oxide Interfaces journal, March 2010

Magnetic effects at the interface between non-magnetic oxides
journal, June 2007

Projector augmented-wave method
journal, December 1994

Oxide Interfaces--An Opportunity for Electronics
journal, March 2010

High Mobility in ${LaAlO}_{3} / {SrTiO}_{3}$ Heterostructures: Origin, Dimensionality, and Perspectives
journal, May 2007

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996

From ultrasoft pseudopotentials to the projector augmented-wave method
journal, January 1999

Charge localization or itineracy at $La Al O_{3} ? Sr Ti O_{3}$ interfaces Hole polarons, oxygen vacancies, and mobile electrons
journal, July 2006

Tunable Quasi-Two-Dimensional Electron Gases in Oxide Heterostructures
journal, September 2006

Why some interfaces cannot be sharp
journal, January 2006

Tunable Rashba Spin-Orbit Interaction at Oxide Interfaces
journal, March 2010