Abstract
We report on a metal-insulator transition in the LaAlO-SrTiO interface electron system, of which the carrier density is tuned by an electric gate field. Below a critical carrier density ranging from 0.5 to , LaAlO-SrTiO interfaces, forming drain-source channels in field-effect devices, are nonohmic. The differential resistance at zero channel bias diverges within a 2 variation of the carrier density. Above , the conductivity of the ohmic channels has a metal-like temperature dependence, while below conductivity sets in only above a threshold electric field. For a given thickness of the LaAlO layer, the conductivity follows a characteristic. The metal-insulator transition is found to be distinct from that of the semiconductor 2D systems.
1 More- Received 2 October 2010
DOI:https://doi.org/10.1103/PhysRevB.83.075402
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