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Digital Tuning of the Transition Temperature of Epitaxial VO 2 Thin Films on MgF 2 Substrates by Strain Engineering
Author(s) -
Howard Sebastian A.,
Evlyukhin Egor,
Páez Fajardo Galo,
Paik Hanjong,
Schlom Darrell G.,
Piper Louis F. J.
Publication year - 2021
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202001790
Subject(s) - materials science , epitaxy , x ray photoelectron spectroscopy , molecular beam epitaxy , transition temperature , atmospheric temperature range , substrate (aquarium) , diffraction , vanadium , strain engineering , thin film , crystallography , analytical chemistry (journal) , condensed matter physics , nanotechnology , layer (electronics) , optoelectronics , chemical engineering , optics , metallurgy , thermodynamics , organic chemistry , silicon , chemistry , oceanography , superconductivity , physics , geology , engineering
Straining the vanadium dimers along the rutile c ‐axis can be used to tune the metal‐to‐insulator transition (MIT) of VO 2 but has thus far been limited to TiO 2 substrates. In this work VO 2 /MgF 2 epitaxial films are grown via molecular beam epitaxy (MBE) to strain engineer the transition temperature ( T MIT ). First, growth parameters are optimized by varying the synthesis temperature of the MgF 2 (001) substrate ( T S ) using a combination of X‐ray diffraction techniques, temperature dependent transport, and soft X‐ray photoelectron spectroscopy. It is determined that T S values greater than 350 °C induce Mg and F interdiffusion and ultimately the relaxation of the VO 2 layer. Using the optimized growth temperature, VO 2 /MgF 2 (101) and (110) films are then synthesized. The three film orientations display MITs with transition temperatures in the range of 15–60 °C through precise strain engineering.