Electronic Phase Transitions of 未-AgxV2O5 Nanowires: Interplay between Geometric and Electronic Structures

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• 作者：Peter M. Marley ; Sujay Singh ; Tesfaye A. Abtew ; Cherno Jaye ; Daniel A. Fischer ; Peihong Zhang ; Ganapathy Sambandamurthy ; Sarbajit Banerjee
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：September 11, 2014
• 年：2014
• 卷：118
• 期：36
• 页码：21235-21243
• 全文大小：465K
• ISSN：1932-7455

文摘

Vanadium oxide bronzes, with the general formula M_xV₂O₅, provide a wealth of compositions and frameworks where strong electron correlation can be systematically (albeit thus far only empirically) tuned. In this work, we report the synthesis of single-crystalline 未-Ag_0.88V₂O₅ nanowires and unravel pronounced electronic phase transitions induced in response to temperature and applied electric field. Specifically, a pronounced semiconductor鈥搒emiconductor transition is evidenced for these materials at ca. 150 K upon heating, and a distinctive insulator鈥揷onductor transition is observed upon application of an in-plane voltage. An orbital-specific picture of the mechanistic basis of the phase transitions is proposed using a combination of density functional theory (DFT) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Structural refinements above and below the transition temperature, angle-resolved O K-edge NEXAFS spectra, and DFT calculations suggest that the electronic phase transitions in these 2D frameworks are mediated by a change in the overlap of d_xy orbitals.