Thickness dependence of electronic structures in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi mathvariant="normal">V</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> ultrathin films: Suppression of the cooperative Mott-Peierls transition
Daisuke Shiga, Bailiang Yang, N. Hasegawa, Tatsuhiko Kanda, Ryosuke Tokunaga, K. Yoshimatsu, Ryu Yukawa, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira
Abstract
The long-standing problem surrounding the metal-insulator transition of VO${}_{2}$ is the relative role of Mott and Peierls instabilities. Here, the authors investigate the change in electronic and crystal structures of nanostructured VO${}_{2}$ films, where the balance between the two instabilities is controlled as a function of thickness. $I\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ photoemission spectroscopy reveals that VO${}_{2}$ in the thin limit exhibits a Mott insulating nature without the V-V dimerization characteristic of bulk VO${}_{2}$, owing to the dominance of the Mott instability over the Peierls one.