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  • The anomalous temperature dependent low energy electron diffraction intensity at epitaxial Sr 3 Ir 2 O 7 thin film surfaces
Title: The anomalous temperature dependent low energy electron diffraction intensity at epitaxial Sr 3 Ir 2 O 7 thin film surfaces
Abstract We report on the temperature dependent low energy electron diffraction (LEED) studies of 12 nm epitaxial Sr3Ir2O7(001) thin films. The Debye temperature has been extracted from the temperature-dependence of LEED intensity at elevated temperatures and different electron kinetic energies. For the most surface sensitive LEED, obtained at the lowest electron kinetic energies, the extracted surface Debye temperature is 270 ± 22 K, which is much lower than the 488 ± 40 K Debye temperature obtained using higher electron kinetic energies. Surprisingly, the LEED diffraction intensity, at the lowest electron kinetic energies, increases rather than decreases, with increasing sample temperatures up to about 440 K. This anomalous behavior has been attributed to the reduction of the lattice vibrational amplitudes along the surface normal. This damping of the normal mode vibrations with increasing temperature results from the enhanced electronic screening via thermally activated carriers. This scenario is corroborated by the transport measurement, showing that Sr3Ir2O7is a narrow band Mott insulator with a band gap of about 32 meV. We have identified criteria for finding anomalous scattering behavior in other transition metal oxide systems.  more » « less
Award ID(s):
2044049
PAR ID:
10636316
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
IOP Science
Date Published:
Journal Name:
Journal of Physics: Condensed Matter
Volume:
37
Issue:
16
ISSN:
0953-8984
Page Range / eLocation ID:
165402
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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