Bulletin of the American Physical Society
APS March Meeting 2012
Volume 57, Number 1
Monday–Friday, February 27–March 2 2012; Boston, Massachusetts
Session V18: Focus Session: Interfaces in Complex Oxides - Interface and Surface Conductivity in SrTiO3
8:00 AM–11:00 AM,
Thursday, March 1, 2012
Sponsoring Unit: DMP
Chair: Stefano Gariglio, Universite de Geneve
Abstract ID: BAPS.2012.MAR.V18.7
Abstract: V18.00007 : Electronic phase separation at the LaAlO$_3$/SrTiO$_3$ interface*
9:12 AM–9:48 AM
Preview Abstract Abstract
(NUSNNI-Nanocore \& Department of Physics, National University of Singapore, Singapore)
In the last few years we have seen a number of new properties to emerge at the interface between two insulating oxides. However the origin of these properties remains unclear and needs further investigation. In this talk I will discuss our recent studies on oxide interfaces in which we vary various parameters such as oxygen content and crystal orientation, and use different polar layers and heterostructures. Surprisingly, at the LaAlO$_3$/SrTiO$_3$ interface a remarkable combination of strong diamagnetism (superconductor like), paramagnetism and ferromagnetism can coexist with the quasi two dimensional electron gas (Q2DEG) when prepared under a more oxidizing condition. The ferromagnetic phase is stable even above room temperature and the diamagnetism below a relatively high temperature of 60 K. Our measurements show that the free surface of SrTiO$_3$ may be responsible for all these fascinating phenomena. The phenomena are explained due to the selective occupancy of interface/surface sub-bands of the nearly degenerate Ti orbital in the SrTiO$_3$. On changing the interface orientation, we unexpectedly can also obtain conductivity at the LaAlO$_3$/SrTiO$_3$ interface prepared on (110)-oriented SrTiO$_3$. The conductivity is found to be highly anisotropic, which is a novel feature for these oxide Q2DEGs and of potential interest for applications. I will discuss various possible models that can explain this intriguing observation and also review various interfaces prepared using different polar layers coupled to other functional materials which result in new phenomena.
*We thank National Research Foundation (NRF) Singapore under the Competitive Research Program (CRP) ``Tailoring Oxide Electronics by Atomic Control'' NRF2008NRF-CRP002-024 and Ministry of Education (MOE) FRC-ARF Grant No. R-144-000-278-112.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.V18.7
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