Epitaxial growth and transport properties of compressively-strained Ba2IrO4 films* *Project supported by the National Natural Science Foundation of China (Grant Nos. 11774153, 11861161004, 51772143, 11974163, and 51672125), the National Key Research and Development Program of China (Grant No. 2016YFA0201104), the Fundamental Research Funds for the Central Universities, China (Grant Nos. 0213-14380167 and 0213-14380198), and the Hong Kong Research Grants Council

Abstract

Ba2IrO4 is a sister compound of the widely investigated Sr2IrO4 and has no IrO6 octahedral rotation nor net canted antiferromagnetic moment, thus it acts as a system more similar to the high-T c cuprate. In this work, we synthesize the Ba2IrO4 epitaxial films by reactive molecular beam epitaxy and study their crystalline structure and transport properties under biaxial compressive strain. High resolution scanning transmission electron microscopy and x-ray diffraction confirm the high quality of films with partial strain relaxation. Under compressive epitaxial strain, the Ba2IrO4 exhibits the strain-driven enhancement of the conductivity, consistent with the band gap narrowing and the stronger hybridization of Ir-t2g and O-2p orbitals predicted in the first-principles calculations.