Abstract

We have investigated structural, transport, and optical properties of tensile strained (Sr1−xLax)3Ir2O7 (x = 0, 0.025, 0.05) epitaxial thin films. While high-Tc superconductivity is predicted theoretically in the system, we have observed that all of the samples remain insulating with finite optical gap energies and Mott variable-range hopping characteristics in transport. Cross-sectional scanning transmission electron microscopy indicates that structural defects such as stacking faults appear in this system. The insulating behavior of the La-doped Sr3Ir2O7 thin films is presumably due to disorder-induced localization and ineffective electron doping of La, which brings to light the intriguing difference between epitaxial thin films and bulk single crystals of the iridates.

Document Type

Article

Publication Date

2-14-2018

Notes/Citation Information

Published in Physical Review Materials, v. 2, issue 2, 024803, p. 1-6.

©2018 American Physical Society

The copyright holder has granted the permission for posting the article here.

Digital Object Identifier (DOI)

https://doi.org/10.1103/PhysRevMaterials.2.024803

Funding Information

We acknowledge the support of NSF Grants No. DMR-1454200 (for thin-film synthesis and characterizations), No. DMR-1265162 and No. DMR-1712101 (for target synthesis), and No. DMR-1262261 (for infrared spectroscopy).

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