Atomically-abrupt interfaces in transition metal oxide (TMO) heterostructures could host a variety of exotic condensed matter phases that may not be found in the bulk materials at equilibrium. A critical step in the development of such atomically-sharp interfaces is the deposition of atomically-smooth TMO thin films. Optimized deposition conditions exist for the growth of perovskite oxides. However, the deposition of rutile oxides, such as VO2, with atomic-layer precision has been challenging. In this work, we used pulsed laser deposition (PLD) to grow atomically-smooth VO2 thin films on rutile TiO2 (101) substrates. We show that optimal substrate preparation procedure followed by the deposition of VO2 films at a temperature conducive for step-flow growth mode is essential for achieving atomically-smooth VO2 films. The films deposited at optimal substrate temperatures show a step and terrace structure of the underlying TiO2 substrate. At lower deposition temperatures, there is a transition to a mixed growth mode comprising of island growth and layer-by-layer growth modes. VO2 films deposited at optimal substrate temperatures undergo a metal to insulator transition at a transition temperature of ∼325 K with ∼103 times increase in resistance, akin to MIT in bulk VO2.
@article{arxiv.1908.02937,
title = {Atomically-Smooth Single-Crystalline VO$_2$ thin films with Bulk-like Metal-Insulator Transitions},
author = {Debasish Mondal and Smruti Rekha Mahapatra and Tanweer Ahmed and Suresh Kumar Podapangi and Arindam Ghosh and Naga Phani B. Aetukuri},
journal= {arXiv preprint arXiv:1908.02937},
year = {2020}
}
Comments
5 pages, 4 figures, Supplementary Information with 2 pages and 1 Figure