Bandwidth controlled metal‐insulator transition in Au–VO₂ nanocomposite thin films

Abstract

Recognizing and controlling the metal-insulator transition (MIT) in VO 2 transition-metal oxides is interesting for the future electronic devices. However, the effect of the electron correlation for the structure-coupled MIT in VO 2 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-VO 2 nanocomposite thin films (NCTFs). A significantly enhancement of the MIT temperature (about 350 K) is realized in Au-VO 2 films with Au volume ratio of 1.1 mol%. However, by further increasing Au ratios, the MIT temperature in Au-VO 2 NCTFs 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 VO 2 is BC-MIT which improved our understanding of the electron correlation effect in VO 2 systems. K E Y W O R D Sbandwidth, metal-insulator transition, vanadium dioxide

Tunable physical properties in Bi-based layered supercell multiferroics embedded with Au nanoparticles

“…41 Au and Pt nanoparticles have been introduced into VO 2 as an effective secondary phase to reduce the phase transition temperature from 360.74 K to 329.16 K or lower. 42,43 Interesting optical dielectric function tuning has been demonstrated in multiple systems including BTO-Au, ZnO-Au, La 0.7 Sr 0.3 MnO 3 -Au, etc. 44,45 In this work, we have combined the newly discovered single phase multiferroic BAMO LSC as the matrix and the plasmonic Au NPs to form a new nanocomposite system.…”

“…41 Au and Pt nanoparticles have been introduced into VO 2 as an effective secondary phase to reduce the phase transition temperature from 360.74 K to 329.16 K or lower. 42,43 Interesting optical dielectric function tuning has been demonstrated in multiple systems including BTO-Au, ZnO–Au, La 0.7 Sr 0.3 MnO 3 –Au, etc. 44,45…”

Mechanical properties study of VO2micro‐beam according to metal‐insulator transition

“…Moreover, a crystal structure change occurs between the monoclinic and rutile, causing a difference in density as the distance between the vanadium atoms changes 6 . Therefore, various applications (e.g., smart windows, transistors, optical switch, and strain sensors) using the MIT of VO 2 have been developed and researched 7‐23 …”

“…6 Therefore, various applications (e.g., smart windows, transistors, optical switch, and strain sensors) using the MIT of VO 2 have been developed and researched. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The difference in the densities of the metal and insulator phases complicates the commercialization of these applications, as it can result in deterioration, disuse, or even fracture of the materials during cycling. Therefore, it is necessary to understand the mechanical properties of each phase in detail.…”

Octahedral Symmetry Modification Induced Orbital Occupancy Variation in VO2

“…Interestingly, the a M /2 b M ratio of 0.580 (symmetric octahedral structure) has a wide fwhm of the pre-edge peak. The wide fwhm indicates a large bandwidth, W , which means that there is a large electron hopping energy. , All fwhms of the pre-edge peak were obtained from a Gaussian fit after removing the background (Figure S6b). Figure c shows the fwhm of the pre-edge peak as a function of the a M /2 b M ratio.…”