Ultrathin epitaxial films of EuNiO3 were grown on a series of substrates traversing highly compressive (- 2.4%) to highly tensile (2.5%) lattice mismatch. X-ray diffraction measurements showed the expected c-lattice parameter shift for compressive strain, but no detectable shift for tensilely strained substrates, while reciprocal space mapping confirmed the tensile strained film maintained epitaxial coherence. Transport measurements showed a successively (from tensile to compressive) lower resistance and a complete suppression of the metalinsulator transition at highly compressive lattice mismatch. Corroborating these findings, X-ray absorption spectroscopy measurements revealed a strong multiplet splitting in the tensile samples that progressively weakens with increasing compressive strain that, combined with cluster calculations, showed enhanced covalence between Ni-d and O-p orbitals leads to the metallic state.
@article{arxiv.1304.1751,
title = {Strain mediated suppression of the metal-insulator transition in EuNiO3 thin films},
author = {D. Meyers and S. Middey and M. Kareev and M. van Veenendaal and E. J. Moon and B. A. Gray and J. W. Freeland and J. Chakhalian},
journal= {arXiv preprint arXiv:1304.1751},
year = {2014}
}