Formation of a conducting LaAlO3/SrTiO3 interface studied by low-energy electron reflection during growth
| Autor: | Chencheng Xu, Jan Aarts, Chunhai Yin, Zhaoliang Liao, Nicolas Gauquelin, A. J. H. van der Torren, S. J. van der Molen |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) business.industry Magnetism 02 engineering and technology Substrate (electronics) Electron Electronic structure 021001 nanoscience & nanotechnology 01 natural sciences Pulsed laser deposition law.invention law 0103 physical sciences Reflection (physics) Optoelectronics General Materials Science Electron microscope 010306 general physics 0210 nano-technology business Layer (electronics) |
| Zdroj: | Physical Review Materials |
| ISSN: | 2475-9953 |
| Popis: | The two-dimensional electron gas occurring between the band insulators SrTiO3 and LaAlO3 continues to attract considerable interest, due to the possibility of dynamic control over the carrier density and due to ensuing phenomena such as magnetism and superconductivity. The formation of this conducting interface is sensitive to the growth conditions, but despite numerous investigations there are still questions about the details of the physics involved. In particular, not much is known about the electronic structure of the growing LaAlO3 layer at the growth temperature (around 800∘C ) in oxygen (pressure around 5×10−5 mbar), since analysis techniques at these conditions are not readily available. We developed a pulsed laser deposition system inside a low-energy electron microscope in order to study this issue. The setup allows for layer-by-layer growth control and in situ measurements of the angle-dependent electron reflection intensity, which can be used as a fingerprint of the electronic structure of the surface layers during growth. By using different substrate terminations and growth conditions we observe two families of reflectivity maps, which we can connect either to samples with an AlO2 -rich surface and a conducting interface or to samples with a LaO-rich surface and an insulating interface. Our observations emphasize that substrate termination and stoichiometry determine the electronic structure of the growing layer, and thereby the conductance of the interface. |
| Databáze: | OpenAIRE |
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