We investigate the structural and transport properties of vacancy-ordered monoclinic superconducting TiO thin films grown by molecular beam epitaxy. The evolution of the crystal structure during growth is monitored by in-situ synchrotron X-ray diffraction. Long-range ordering of Ti and O vacancies in the disordered cubic phase stabilizes the vacancy-ordered monoclinic TiO phase. The reduced structural disorder arising from vacancy-ordering is correlated with a superconductor-metal transition (SMT) in contrast to the superconductor-insulator transition (SIT) observed in cubic TiO, orthorhombic Ti2O3, and the Magneli γ−Ti3O5 and γ−Ti4O7 phase. Magnetoresistance measurements for the SIT phases indicate superconducting fluctuations persisting in the normal phase. These results confirm the role of disorder related to Ti and O vacancies and structural inhomogeneity in determining the electronic properties of the normal state of titanium oxide-based superconductors.
@article{arxiv.2305.16973,
title = {In-situ scattering studies of superconducting vacancy-ordered monoclinic TiO thin films},
author = {Merve Baksi and Hawoong Hong and Divine P. Kumah},
journal= {arXiv preprint arXiv:2305.16973},
year = {2023}
}