Search

Recognizing and controlling the metal‐insulator transition (MIT) in VO2 transition‐metal oxides is interesting for the future electronic devices. However, the effect of the electron correlation for the structure‐coupled MIT in VO2 is as yet an open question. In this study, we present for the first time direct spectroscopic evidence for the charge‐transfer assistance bandwidth controlled MIT (BC‐MIT) in Au–VO2 nanocomposite thin films (NCTFs). A significantly enhancement of the MIT temperature (about 350 K) is realized in Au–VO2 films with Au volume ratio of 1.1 mol%. However, by further increasing Au ratios, the MIT temperature in Au–VO2NCTFs is downward shifted by ~16 K and forward shifted 6 K. The V L‐edge and O K‐edge have been investigated. The basic electronic parameters such as the covalency (W) have been tuned. The relationship between bandwidth and the MIT temperature has been clearly elucidated a linear relationship. The experimental results demonstrate that MIT in VO2 is BC‐MIT which improved our understanding of the electron correlation effect in VO2 systems. [ABSTRACT FROM AUTHOR]

Polycrystalline Cd1− xBa xO (0 ≤ x ≤ 0.08) ceramics were synthesized via conventional solid-state reaction method, and the effect of Ba2+ doping on the microstructure as well as the thermoelectric transport properties of the samples were investigated. It was found that doping of Ba2+ can inhibit the grain growth of CdO, resulting in a considerable reduction in grain size. Moreover, with the increase in Ba2+ doping content, both the electrical conductivity and the thermal conductivity of Cd1− xBa xO decreased, whereas the Seebeck coefficient increased. A high ZT value of 0.47 was achieved for Cd0.99Ba0.01O at 1000 K, 38% higher than the undoped CdO, mostly due to reduction of the thermal conductivity. [ABSTRACT FROM AUTHOR]