Thermopower analysis of metal-insulator transition temperature modulations in vanadium dioxide thin films with lattice distortion

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, (11-20) alpha-Al2O3, and (001) TiO2 substrates, showed significant decrease of absolute value of Seebeck coefficient (S) from ~200 to 23 microV K-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 (Trho) and S (TS) for the VO2 films systematically decrease with lattice shrinkage in the pseudo-rutile structure along c-axis, accompanying a broadening of the MI transition temperature width. Moreover, the onset TS, where the insulating phase starts to become metallic, is much lower than onset Trho. 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.

arXiv commentTo be published in Physical Review B

References in corpus (6)

• Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging
• Strain engineering and one-dimensional organization of metal-insulator domains in single-crystal VO2 beams
• Measurement of a solid-state triple point at the metal-insulator transition in VO2
• Nanoscale imaging of the electronic and structural transitions in vanadium dioxide
• Experimental characterization of the electronic structure of anatase TiO2: Thermopower modulation
• Thermopower analysis of the electronic structure around metal-insulator transition in V1-xWxO2

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