Direct observation of a two-dimensional hole gas at oxide interfaces
| Autor: | Bumsu Park, Jung-Woo Lee, Sang Ho Oh, Jung Woo T. Seo, Mark Rzchowski, Neil Campbell, Leonard J. Brillson, H. Zhou, Evgeny Y. Tsymbal, Brenton A. Noesges, Tula R. Paudel, Thaddeus J. Asel, Chang-Beom Eom, Ja Kyung Lee, Hyungwoo Lee |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
business.industry
Mechanical Engineering Oxide Heterojunction Cathodoluminescence 02 engineering and technology General Chemistry Partial pressure 021001 nanoscience & nanotechnology Condensed Matter Physics Epitaxy 01 natural sciences Crystallographic defect Electron holography chemistry.chemical_compound chemistry Mechanics of Materials 0103 physical sciences Optoelectronics General Materials Science 010306 general physics 0210 nano-technology business Fermi gas |
| Zdroj: | Nature materials. 17(3) |
| ISSN: | 1476-4660 |
| Popis: | The discovery of a two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface 1 has resulted in the observation of many properties2–5 not present in conventional semiconductor heterostructures, and so become a focal point for device applications6–8. 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 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. 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 SrTiO3/LaAlO3/SrTiO3 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink