Strain-induced structural transition of rutile type ReO_2 epitaxial thin films

摘要

Rutile-related (tetragonal rutile and monoclinic distorted rutile) ReO_2 epitaxial thin films were grown on rutile TiO_2 single crystalline substrates by reactive pulsed laser deposition of the Re metal target under a N_2O atmosphere. The ReO_2 film underwent structural phase transition from the monoclinic to tetragonal phase with the decreasing film thickness, driven by compressive lattice strain from the substrate. X-ray photoelectron spec-troscopy and electrical transport measurements revealed that both phases had metallic properties above 25 K. The distinct difference in valence band spectra between the two phases might be due to reconstruction of the band structure dominated by Re 5d t_(2g).