Metallic ground states of undoped Ti2O3 films induced by elongated c-axis lattice constant

Abstract Ti2O3 exhibits unique metal–insulator transition (MIT) at ~ 450 K over a wide temperature range of ~ 150 K. The close relationship between MIT and crystal deformation has been proposed. However, as physical properties are governed by the thermodynamic equilibrium in bulk systems, conducting...

Full description

Saved in:
Bibliographic Details
Main Authors: K. Yoshimatsu, N. Hasegawa, Y. Nambu, Y. Ishii, Y. Wakabayashi, H. Kumigashira
Format: article
Language:EN
Published: Nature Portfolio 2020
Subjects:
R
Q
Online Access:https://doaj.org/article/baa44c2bc7f342ff94ee9c4fcb8a871e
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Ti2O3 exhibits unique metal–insulator transition (MIT) at ~ 450 K over a wide temperature range of ~ 150 K. The close relationship between MIT and crystal deformation has been proposed. However, as physical properties are governed by the thermodynamic equilibrium in bulk systems, conducting experimental studies under different lattice deformations remains challenging. Epitaxial thin films can offer high flexibility to accommodate adaptive crystal lattices and provide efficient platforms for investigating the MIT. In this study, we report the synthesis of corundum-type Ti2O3 films on various growth temperatures. We found that the metallic ground states appeared in the films grown at low temperatures. The electronic ground states were further investigated by the electronic-structure calculations. Results suggest that the electrical properties of Ti2O3 films were governed by the c/a ratio of the crystal structure, and the absence of the MIT was attributed to the lattice deformation characterized by an elongated c lattice constant.