University of Minnesota
School of Physics & Astronomy

Condensed Matter Seminar

Thursday, November 19th 2009
1:25 pm:
Condensed Matter Seminar in 210 Physics
Speaker: Jeremy Levy, University of Pittsburgh
Subject: Possible Observation of Integer and Fractional Quantum Hall States in an Interfacial Oxide Nanostructure

The discovery of a high-mobility two-dimensional electron gas at the interface between a polar and non-polar insulating oxide has motivated transport experiments aiming at eliciting various quantum effects. At room temperature, an electric field-tunable hysteretic metal-insulator transition was discovered. At low temperatures (below 1 K), interfacial superconductivity and magnetism were reported. Here, I describe low-temperature magnetotransport experiments in a nanowire formed at the interface between LaAlO3 and SrTiO3. Distinct plateaus are observed and associated with quantized magnetoresistance at integer and fractional Landau level filling factors ν=2,3,...,9, and the fractional filling factors ν=7/3 and 11/5. The quasi-one-dimensional nature of the conducting channel, combined with the large electric field-tunable dielectric permittivity of SrTiO3, is believed to contribute to the stability of the integer and fractional quantum Hall states.

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