The control of metal-insulator transition in vanadium dioxide
Abstract/Contents
- Abstract
- The external control of the conductivity of correlated oxides is one of the most promising avenues towards realizing energy-efficient electronic devices. One of the prime candidates for such devices, vanadium dioxide (VO2), undergoes a temperature-driven metal-insulator transition (MIT) near room temperature (~340 K) with a concomitant change in crystal symmetry. First, using epitaxial strain provided by a variable thickness RuO2 buffer layer, we vary the MIT transition temperature of VO2 (001) films continuously from ~285 to ~345 K. We show, using strain-, polarization- and temperature-dependent x-ray absorption spectroscopy, in conjunction with x-ray diffraction and electrical transport measurements, that the transition temperature (TMIT) of VO2 is controlled by the orbital occupancy in its metallic state. Our results furthermore indicate that the magnitude of the structural distortion across the transition is also directly related to the orbital occupation in the metallic state. This work opens up the possibility of controlling the nature of the conducting state in atomically thin VO2 layers by manipulating the orbital occupancy by, for example, hetero-structural engineering. In a related study, we have used a combination of electron-beam and optical lithography to fabricate lateral two-terminal nano-devices from VO2 films deposited on TiO2 (001) substrates without RuO2 buffer layers. In these devices, we show that the transition can also be engendered by the application of modest electric fields, several orders of magnitude below the electric breakdown field, making this phenomenon potentially useful for two or three terminal switches. The delay time before switching is found to decrease with increasing electric field and temperature. We discuss whether these results indicate the transition is dominated by electronic or by Joule heating effects. These results demonstrate the possibility of triggering an MIT at low voltages and, therefore, at low energies, which is essential for device applications. Finally, we also discuss MIT in VO2-TiO2 based hetero-structures. We show that the temperature-driven MIT persists in VO2 films as thin as 1.8 nm.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Aetukuri, Naga Phani B |
|---|---|
| Associated with | Stanford University, Department of Materials Science and Engineering. |
| Primary advisor | Harris, J. S. (James Stewart), 1942- |
| Primary advisor | McIntyre, Paul Cameron |
| Primary advisor | Parkin, Stuart S. P |
| Thesis advisor | Harris, J. S. (James Stewart), 1942- |
| Thesis advisor | McIntyre, Paul Cameron |
| Thesis advisor | Parkin, Stuart S. P |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Naga Phani B. Aetukuri. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Naga Phani Babu Aetukuri
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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