Massively strained VO2 thin film growth on RuO2

Abstract

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 VO${}_2$/RuO${}_2$ system along the c axis of the rutile structure. We have grown VO${}_2$ thin films on single domain RuO${}_2$ 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 VO${}_2$ films to grow indeed fully strained on RuO${}_2$(110), exhibiting a previously unreported ($2\times 2$) reconstruction. On TiO${}_2$(110) substrates, we reproduce this reconstruction and attribute it to an oxygen-rich termination caused by the high oxygen chemical potential. On RuO${}_2$(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.

12 pages, 6 figures. To be published in Crystal Growth & Design

References in corpus (3)

• Direct Observation of Decoupled Structural and Electronic Transitions and an Ambient Pressure Monoclinic-Like Metallic Phase of VO${}_2$
• Large epitaxial bi-axial strain induces a Mott-like phase transition in VO2
• Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO${}_2$