Bandwidth-controlled metal-insulator transition in epitaxial PrNiO_3 ultrathin films induced by dimensional crossover

摘要

The authors have investigated the thickness-dependent physical properties of PrNiO_3 ultrathin films epitaxially grown on LaAlO_3 substrates. The strained PrNiO_3 films exhibit metallic behavior and do not show any indication of temperature-driven metal-insulator transition (MIT) in bulk form, whereas an insulating ground state is realized in a thin limit. In situ photoemission measurements reveal that the observed thickness-dependent MIT is caused by the reduction in bandwidth due to the dimensional control of the films. These results strongly suggest that the MIT in PrNiO_3 films can be controlled by changing the dimensionality under epitaxial constraint.