Dichotomy of the photo-induced 2-dimensional electron gas on SrTiO3 surface terminations

Slavko N. Rebec; Tao Jia; Hafiz M. Sohail; Makoto Hashimoto; Donghui Lu; Zhi Xun Shen; Robert G. Moore

doi:10.1073/pnas.1821937116

Dichotomy of the photo-induced 2-dimensional electron gas on SrTiO₃ surface terminations

Slavko N. Rebec, Tao Jia, Hafiz M. Sohail, Makoto Hashimoto, Donghui Lu, Zhi Xun Shen, Robert G. Moore

Research output: Contribution to journal › Article › peer-review

13 Scopus citations

Abstract

Oxide materials are important candidates for the next generation of electronics due to a wide array of desired properties, which they can exhibit alone or when combined with other materials. While SrTiO₃ (STO) is often considered a prototypical oxide, it, too, hosts a wide array of unusual properties, including a 2-dimensional electron gas (2DEG), which can form at the surface when exposed to ultraviolet (UV) light. Using layer-by-layer growth of high-quality STO films, we show that the 2DEG only forms with the SrO termination and not with the TiO₂ termination, contrary to expectation. This dichotomy of the observed angle-resolved photoemission spectroscopy (ARPES) spectra is similarly seen in BaTiO₃ (BTO), in which the 2DEG is only observed for BaO-terminated films. These results will allow for a deeper understanding and better control of the electronic structure of titanate films, substrates, and heterostructures.

Original language	English
Pages (from-to)	16687-16691
Number of pages	5
Journal	Proceedings of the National Academy of Sciences of the United States of America
Volume	116
Issue number	34
DOIs	https://doi.org/10.1073/pnas.1821937116
State	Published - Aug 20 2019
Externally published	Yes

Funding

We thank Z. Y. Chen, H. Y. Hwang, and B. Moritz for fruitful discussions. This work was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division Contract DE-AC02-76SF00515. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences Contract DE-AC02-76SF00515. Part of this work was performed at the Stanford Nano Shared Facilities, supported by NSF Award ECCS-1542152. ACKNOWLEDGMENTS. We thank Z. Y. Chen, H. Y. Hwang, and B. Moritz for fruitful discussions. This work was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division Contract DE-AC02-76SF00515. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences Contract DE-AC02-76SF00515. Part of this work was performed at the Stanford Nano Shared Facilities, supported by NSF Award ECCS-1542152.

Funders	Funder number
US Department of Energy
Basic Energy Sciences
U.S. Department of Energy
Office of Science
National Sleep Foundation
Office of Basic Energy Sciences
National Science Foundation	1542152
National Science Foundation
Division of Materials Sciences and Engineering	DE-AC02-76SF00515
Division of Materials Sciences and Engineering

Keywords

2-dimensional electron gas
Molecular beam epitaxy
Strontium titanate
Termination control

Access to Document

10.1073/pnas.1821937116

Cite this

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title = "Dichotomy of the photo-induced 2-dimensional electron gas on SrTiO3 surface terminations",

abstract = "Oxide materials are important candidates for the next generation of electronics due to a wide array of desired properties, which they can exhibit alone or when combined with other materials. While SrTiO3 (STO) is often considered a prototypical oxide, it, too, hosts a wide array of unusual properties, including a 2-dimensional electron gas (2DEG), which can form at the surface when exposed to ultraviolet (UV) light. Using layer-by-layer growth of high-quality STO films, we show that the 2DEG only forms with the SrO termination and not with the TiO2 termination, contrary to expectation. This dichotomy of the observed angle-resolved photoemission spectroscopy (ARPES) spectra is similarly seen in BaTiO3 (BTO), in which the 2DEG is only observed for BaO-terminated films. These results will allow for a deeper understanding and better control of the electronic structure of titanate films, substrates, and heterostructures.",

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AU - Rebec, Slavko N.

AU - Jia, Tao

AU - Sohail, Hafiz M.

AU - Hashimoto, Makoto

AU - Lu, Donghui

AU - Shen, Zhi Xun

AU - Moore, Robert G.

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N2 - Oxide materials are important candidates for the next generation of electronics due to a wide array of desired properties, which they can exhibit alone or when combined with other materials. While SrTiO3 (STO) is often considered a prototypical oxide, it, too, hosts a wide array of unusual properties, including a 2-dimensional electron gas (2DEG), which can form at the surface when exposed to ultraviolet (UV) light. Using layer-by-layer growth of high-quality STO films, we show that the 2DEG only forms with the SrO termination and not with the TiO2 termination, contrary to expectation. This dichotomy of the observed angle-resolved photoemission spectroscopy (ARPES) spectra is similarly seen in BaTiO3 (BTO), in which the 2DEG is only observed for BaO-terminated films. These results will allow for a deeper understanding and better control of the electronic structure of titanate films, substrates, and heterostructures.

AB - Oxide materials are important candidates for the next generation of electronics due to a wide array of desired properties, which they can exhibit alone or when combined with other materials. While SrTiO3 (STO) is often considered a prototypical oxide, it, too, hosts a wide array of unusual properties, including a 2-dimensional electron gas (2DEG), which can form at the surface when exposed to ultraviolet (UV) light. Using layer-by-layer growth of high-quality STO films, we show that the 2DEG only forms with the SrO termination and not with the TiO2 termination, contrary to expectation. This dichotomy of the observed angle-resolved photoemission spectroscopy (ARPES) spectra is similarly seen in BaTiO3 (BTO), in which the 2DEG is only observed for BaO-terminated films. These results will allow for a deeper understanding and better control of the electronic structure of titanate films, substrates, and heterostructures.

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