C. Rayan Serrao, Jian Liu, J. T. Heron, G. Singh-Bhalla, A. Yadav, S. J. Suresha, J. Ravichandran, R. J. Paull, Y. Di, J. -H. Chu, M. Trassin, A. Vishwanath, E. Arenholz, X. Marti, R. Ramesh
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 stress up to ~0.3% drops the c/a tetragonality by 1.2 %. X-ray absorption spectroscopy detected a severe reduction of the linear dichroism upon increasing in-plane tensile strain towards a reduced anisotropy in the electronic structure. While the most relaxed thin film shows a consistent dependence with previously reported single crystal measurements, electrical transport reveals an energy gap reduction of ~ 200% for the thinnest and most epitaxy-distorted film. We argue that reduced tetragonality plays a major role in the electronic reconstruction, which reflects in the transport properties. This manuscript sets up the stage for exploiting epitaxial strain as a systematic tool for both structural and functional manipulation of 5d correlated oxides.
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http://arxiv.org/abs/1210.0161
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