Giant Thermopower in Quasi-One-Dimensional LaAlO<sub>3</sub>/SrTiO<sub>3</sub> Quantum Wires

ORAL

Abstract

SrTiO3-based heterointerfaces possess new effects ranging from superconductivity to magnetism. In particular, the two-dimensional (2D) LaAlO3/SrTiO3 interface was previously shown to have highly enhanced and oscillating thermopower when back-gated close to the insulating state [1]. Here we investigated the electrical and thermoelectric transport properties of quasi-one-dimensional (1D) LaAlO3/SrTiO3 quantum wires [2] at a low temperature of 80 mK. We find significantly enhanced and oscillating thermopower for the quantum wires, with values that are comparable to reports for 2D LaAlO3/SrTiO3 [1]. The Mott relation, which governs the diffusive thermopower of non-interacting electrons, works surprisingly well despite the highly ballistic nature of electron transport and evidence of electron-electron interaction in these quantum wires. Our results suggest that the highly enhanced thermopower in 2D SrTiO3-based systems may originate from naturally formed quasi-1D channels at the heterointerfaces.

[1] I. Pallecchi et al., Nature Communications 6, 6678 (2015).
[2] A. Annadi et al., Nano Lett 18, 4473 (2018).

*JL acknowledges a Vannevar Bush Faculty Fellowship (ONR N00014-15-1-2847). C-BE acknowledges NSF DMREF (DMR-1629270), AFOSR (FA9550-15-1-0334), and AOARD (FA2386-15-1-4046).

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Presenters

  • Puqing Jiang

    • Department of Physics and Astronomy, University of Pittsburgh

Authors

  • Puqing Jiang

    • Department of Physics and Astronomy, University of Pittsburgh

  • Yuhe Tang

    • Department of Physics and Astronomy, University of Pittsburgh
    • Univ of Pittsburgh

  • Hyungwoo Lee

    • Department of Materials Science and Engineering, University of Wisconsin-Madison
    • University of Wisconsin–Madison

  • Jung-Woo Lee

    • Univ of Wisconsin-Madison
    • Materials Science and Engineering, University of Wisconsin-Madison
    • Department of Materials Science and Engineering, University of Wisconsin-Madison
    • University of Wisconsin–Madison
    • Department of Materials Science and Engineering, University of Wisconsin at Madison

  • Chang-Beom Eom

    • Univ of Wisconsin-Madison
    • Materials Science and Engineering, University of Wisconsin-Madison
    • University of Wisconsin–Madison
    • Department of Materials Science and Engineering, University of Wisconsin-Madison
    • Materials Science & Engineering, University of Wisconsin-Madison
    • University of Wisconsin - Madison
    • Department of Materials Science and Engineering, University of Wisconsin - Madison
    • Department of Materials Science and Engineering, University of Wisconsin at Madison

  • Patrick Irvin

    • Univ of Pittsburgh
    • Physics & Astronomy, University of Pittsburgh
    • Department of Physics and Astronomy, University of Pittsburgh
    • Physics and Astronomy, University of Pittsburgh

  • Jeremy Levy

    • Univ of Pittsburgh
    • Physics & Astronomy, University of Pittsburgh
    • Department of Physics and Astronomy, University of Pittsburgh
    • Physics and Astronomy, University of Pittsburgh