Effects of thickness on the metal-insulator transition in free-standing vanadium dioxide nanocrystals

Date
2017
Authors
Fadlelmula, M. M.
Sürmeli, E. C.
Ramezani, M.
Kasırga, T. S.
Advisor
Instructor
Source Title
Nano Letters
Print ISSN
1530-6984
Electronic ISSN
Publisher
American Chemical Society
Volume
17
Issue
3
Pages
1762 - 1767
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

Controlling solid state phase transitions via external stimuli offers rich physics along with possibilities of unparalleled applications in electronics and optics. The well-known metal-insulator transition (MIT) in vanadium dioxide (VO2) is one instance of such phase transitions emerging from strong electronic correlations. Inducing the MIT using electric field has been investigated extensively for the applications in electrical and ultrafast optical switching. However, as the Thomas-Fermi screening length is very short, for considerable alteration in the material’s properties with electric field induced MIT, crystals below 10 nm are needed. So far, the only way to achieve thin crystals of VO2 has been via epitaxial growth techniques. Yet, stress due to lattice mismatch as well as interdiffusion with the substrate complicate the studies. Here, we show that free-standing vapor-phase grown crystals of VO2 can be milled down to the desired thickness using argon ion-beam milling without compromising their electronic and structural properties. Among our results, we show that even below 4 nm thickness the MIT persists and the transition temperature is lowered in two-terminal devices as the crystal gets thinner. The findings in this Letter can be applied to similar strongly correlated materials to study quantum confinement effects.

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Keywords
Argon ion beam milling, Metal−insulator transition, Strongly correlated materials, Vanadium dioxide, Argon, Electric fields, Ion beams, Lattice mismatch, Metal insulator boundaries, Milling (machining), Semiconductor insulator boundaries, Vanadium, Argon ion beam, Electronic and structural properties, Quantum confinement effects, Solid-state phase transition, Strong electronic correlations, Strongly correlated materials, Ultrafast optical switching, Vanadium dioxide, Metal insulator transition
Citation
Published Version (Please cite this version)