Tunnelling into the twisted Mott insulator Sr2IrO4 with atomic resolution

ORAL

Abstract

We studied the single-layered iridate Sr$_2$IrO$_4$ with a scanning tunneling microscope. The finite low temperature conductance enables the electronic structure of this antiferromagnetic Mott insulator to be measured by tunneling spectroscopy. We imaged the topography of freshly cleaved surfaces and measured differential tunneling conductance at cryogenic temperatures. We found the Mott gap in the tunneling density of states to be 2$\Delta$ = 615 meV. Within the Mott gap, additional shoulders are observed which are interpreted as inelastic loss features due to magnons.

*This research was supported by NSF grants DMR- 0800367, DMR-0856234 and EPS-0814194. Noah Bray- Ali acknowledges support from the National Research Council Postdoctoral Research Associateship Program.

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Authors

  • Armin Ansary

    • Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055

  • J. Nichols

    • Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055
    • University of Kentucky
    • Dept. of Physics and Astronomy, University of Kentucky

  • Noah Bray-Ali

    • Joint Quantum Institute, University of Maryland, College Park, Maryland 20742-4111

  • Gang Cao

    • Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky
    • University of Kentucky

  • Kwok-Wai Ng

    • Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055