Direct observation of a two-dimensional hole gas at oxide interfaces
The discovery of a two-dimensional electron gas (2DEG) at the LaAlO 3 /SrTiO 3 interface 1 has resulted in the observation of many properties 2 – 5 not present in conventional semiconductor heterostructures, and so become a focal point for device applications 6 – 8 . Its counterpart, the two-dimensi...
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Published in | Nature materials Vol. 17; no. 3; pp. 231 - 236 |
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Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.03.2018
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | The discovery of a two-dimensional electron gas (2DEG) at the LaAlO
3
/SrTiO
3
interface
1
has resulted in the observation of many properties
2
–
5
not present in conventional semiconductor heterostructures, and so become a focal point for device applications
6
–
8
. Its counterpart, the two-dimensional hole gas (2DHG), is expected to complement the 2DEG. However, although the 2DEG has been widely observed
9
, the 2DHG has proved elusive. Herein 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. 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.
A SrTiO
3
/LaAlO
3
/SrTiO
3
heterostructure is fabricated in high oxygen partial pressure to prevent oxygen vacancy formation. Electrical transport and electron holography directly observes a highly mobile two dimensional hole gas at the top interface. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 AC02-06CH11357; FG02-06ER46327; DMR-1629270; DMR-1420645; DMR-1305193; FA9550-15-1-0334; FA2386-15-1-4046 USDOE Office of Science (SC), Basic Energy Sciences (BES) National Science Foundation (NSF) |
ISSN: | 1476-1122 1476-4660 |
DOI: | 10.1038/s41563-017-0002-4 |