High quality epitaxial thin films of Jeff=1/2 Mott insulator Sr2IrO4 with increasing in-plane tensile strain have been grown on top of SrTiO3(001) substrates. Increasing the in-plane tensile strain up to ~0.3% was observed to drop the c/a tetragonality by 1.2 %. X-ray absorption spectroscopy detected a strong reduction of the linear dichroism upon increasing in-plane tensile strain towards a reduced anisotropy in the local electronic structure. While the most relaxed thin film shows a consistent dependence with previously reported single crystal bulk measurements, electrical transport reveals a charge gap reduction from 200 meV down to 50 meV for the thinnest and most epitaxy-distorted film. We argue that the reduced tetragonality plays a major role in the change of the electronic structure, which is reflected in the change of the transport properties. Our work opens the possibility for exploiting epitaxial strain as a tool for both structural and functional manipulation of spin-orbit Mott systems.
@article{arxiv.1210.0161,
title = {Epitaxy-distorted spin-orbit Mott insulator in Sr2IrO4 thin films},
author = {C. Rayan Serrao and Jian Liu and J. T. Heron and G. Singh-Bhalla and A. Yadav and S. J. Suresha and R. J. Paull and D. Yi and J. -H. Chu and M. Trassin and A. Vishwanath and E. Arenholz and C. Frontera and J. Železný and T. Jungwirth and X. Marti and R. Ramesh},
journal= {arXiv preprint arXiv:1210.0161},
year = {2015}
}