Strain engineering vanadium dioxide thin films is one way to alter this material's characteristic first order transition from semiconductor to metal. In this study we extend the exploitable strain regime by utilizing the very large lattice mismatch of 8.78 % occurring in the VO2/RuO2 system along the c axis of the rutile structure. We have grown VO2 thin films on single domain RuO2 islands of two distinct surface orientations by atomic oxygen-supported reactive MBE. These films were examined by spatially resolved photoelectron and x-ray absorption spectroscopy, confirming the correct stoichiometry. Low energy electron diffraction then reveals the VO2 films to grow indeed fully strained on RuO2(110), exhibiting a previously unreported (2×2) reconstruction. On TiO2(110) substrates, we reproduce this reconstruction and attribute it to an oxygen-rich termination caused by the high oxygen chemical potential. On RuO2(100) on the other hand, the films grow fully relaxed. Hence, the presented growth method allows for simultaneous access to a remarkable strain window ranging from bulk-like structures to massively strained regions.
@article{arxiv.2003.02723,
title = {Massively strained VO2 thin film growth on RuO2},
author = {Simon Fischer and Jon-Olaf Krisponeit and Michael Foerster and Lucia Aballe and Jens Falta and Jan Ingo Flege},
journal= {arXiv preprint arXiv:2003.02723},
year = {2020}
}
Comments
12 pages, 6 figures. To be published in Crystal Growth & Design