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arXiv · 1802.02762

Electronic and optical properties of La-doped Sr$_3$Ir$_2$O$_7$ epitaxial thin-films

M. Souri·J. Terzic·J. M. Johnson·J. G. Connell·J. H. Gruenewald·J. Thompson·J. W. Brill·J. Hwang·G. Cao·A. Seo
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Abstract

We have investigated structural, transport, and optical properties of tensile strained (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ (x = 0, 0.025, 0.05) epitaxial thin-films. While High-T$_c$ 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 Sr$_3$Ir$_2$O$_7$ 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.

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M. Souri, J. Terzic, J. M. Johnson, J. G. Connell, J. H. Gruenewald, J. Thompson, J. W. Brill, J. Hwang, G. Cao, A. Seo. 2018-02-08. Electronic and optical properties of La-doped Sr$_3$Ir$_2$O$_7$ epitaxial thin-films. https://doi.org/10.1103/physrevmaterials.2.024803

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