Abstract
We have studied thin films grown on (3×1)-reconstructed (110) substrates. Films with thicknesses less than the critical thickness of unit cells are insulating in the measured temperature () range (2–400 K). However, films with thicknesses slightly over exhibit reentrant nonmetallic behavior at low temperatures in addition to the normally observed metal-insulator transition at higher temperatures. In contrast, the magnetization does not show signs of low- transitions. Such reentrance of a low- nonmetallic phase is affected by the film thickness as well as the density of oxygen vacancies. The electrical resistivity analysis reveals that localization effects are responsible for the reentrant nonmetallic behavior, which is enhanced with reduced film thickness.
- Received 5 May 2017
- Revised 14 July 2017
DOI:https://doi.org/10.1103/PhysRevMaterials.1.034405
©2017 American Physical Society