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.
|Journal||Physical Review Materials|
|State||Published - Feb 14 2018|
Bibliographical noteFunding 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).
© 2018 American Physical Society.
ASJC Scopus subject areas
- Materials Science (all)
- Physics and Astronomy (miscellaneous)