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Updated: May 23, 2025

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
Emergence of a metallic surface state for narrow bandgap Mott insulator Sr3Ir2O7(001) thin films
Takashi Komesu1, Yuanyuan Zhang1, Shiv Kumar2
1Department of Physics and Astronomy, Theodore Jorgensen Hall, University of Nebraska, 855 N 16th, Lincoln, NE 68588-0299, United States of America.
Abstract:
We report evidence of a finite density of states at the Fermi level at the surface of epitaxial thin films of the narrow bandgap Mott insulator Sr3Ir2O7(001). The Brillouin zone critical points for Sr3Ir2O7(001) thin films have been determined by a comparison of the band mapping from angle-resolved photoemission spectroscopy and low energy electron diffraction. Angle-resolved x-ray photoemission studies reveal the surface termination of Sr3Ir2O7(001) is Sr-O. The absence of dispersion with photon energy, or changing wave vector along the surface normal, indicates the two-dimensional character of the bands contributing to the density of states close to the Fermi level for Sr3Ir2O7(001) thin films. Thus, the finite density of states at the Fermi level is attributed to surface states or surface resonances. The appearance of a finite density of states at the Fermi level is consistent with the increased conductivity with decreasing film thickness for ultrathin Sr3Ir2O7(001) films.
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