Critical thickness of electrical condition for LaAlO3/SrTiO3 heterostructure capped by SrTiO3
Abstract
It is known that a two dimensional electron gas can be formed at the interface of LaAlO3/SrTiO3 (LAO/STO) bilayer. It has been shown that if the LAO thickness exceed 4-unit cell (uc), giving a finite conductivity. We have fabricated a LAO/STO bilayer capped by STO layer and studied the electrical transport properties such oxide trilayer. We have found that the STO/LAO/STO trilayer exhibited electrical conduction even when the LAO thickness is less than 4 uc. We have measured the conductivity of the (STO)n/(LAO)m/STO trilayer with varying m and n. The trilayer begins to exhibit non-zero electrical conduction when m+n = 4. Our experimental observation is consistent the theoretical calculation, which predicted that band gap decreases with the increase of m and n and finally disappear at the critical thickness of m+n = 4. Our trilayer system is found to be robust to the moisture exposure and thermal cycling, implying that our oxide trilayer system can be useful for practical device applications.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- 2018
- Bibcode:
- 2018APS..MARV09009H