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Thermopower analysis of metal-insulator transition temperature modulations in vanadium dioxide thin films with lattice distortion
| Title: | Thermopower analysis of metal-insulator transition temperature modulations in vanadium dioxide thin films with lattice distortion |
| Authors: | Katase, Takayoshi Browse this author | | Endo, Kenji Browse this author | | Ohta, Hiromichi Browse this author →KAKEN DB |
| Issue Date: | 13-Jul-2015 |
| Publisher: | American Physical Society |
| Journal Title: | Physical review B |
| Volume: | 92 |
| Issue: | 3 |
| Start Page: | 35302-1 |
| End Page: | 35302-7 |
| Publisher DOI: | 10.1103/PhysRevB.92.035302 |
| Abstract: | Insulator-to-metal (MI) phase transition in vanadium dioxide (VO2) thin films with controlled lattice distortion was investigated by thermopower measurements. VO2 epitaxial films with different crystallographic orientations, grown on (0001) alpha-Al2O3, (11 (2) over bar0) alpha-Al2O3, and (001) TiO2 substrates, showed significant decrease of absolute value of Seebeck coefficient (S) from similar to 200 to 23 mu VK-1, along with a sharp drop in electrical resistivity (rho), due to the transition from an insulator to a metal. The MI transition temperatures observed both in rho(T-rho) and S(T-S) for the VO2 films systematically decrease with lattice shrinkage in the pseudorutile structure along the c axis, accompanying a broadening of the MI transition temperature width. Moreover, the onset T-S, where the insulating phase starts to become metallic, is much lower than the onset T-rho. This difference is attributed to the sensitivity of S for the detection of hidden metallic domains in the majority insulating phase, which cannot be detected in rho measurements. Consequently, S measurements provide a straightforward and excellent approach for a deeper understanding of the MI transition process in VO2. |
| Rights: | ©2015 American Physical Society |
| Type: | article |
| URI: | http://hdl.handle.net/2115/59763 |
| Appears in Collections: | 電子科学研究所 (Research Institute for Electronic Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 片瀬 貴義
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