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Structure‐Induced Switching of the Band Gap, Charge Order, and Correlation Strength in Ternary Vanadium Oxide Bronzes
Author(s) -
Tolhurst Thomas M.,
Andrews Justin L.,
Leedahl Brett,
Marley Peter M.,
Banerjee Sarbajit,
Moewes Alexander
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700962
Subject(s) - band gap , materials science , charge ordering , ternary operation , condensed matter physics , vanadium oxide , density functional theory , electronic band structure , octahedron , electronic structure , vanadium , charge (physics) , crystallography , crystal structure , chemistry , optoelectronics , physics , computational chemistry , quantum mechanics , computer science , metallurgy , programming language
Recently, V 2 O 5 nanowires have been synthesized as several different polymorphs, and as correlated bronzes with cations intercalated between the layers of edge‐ and corner‐ sharing VO 6 octahedra. Unlike extended crystals, which tend to be plagued by substantial local variations in stoichiometry, nanowires of correlated bronzes exhibit precise charge ordering, thereby giving rise to pronounced electron correlation effects. These developments have greatly broadened the scope of research, and promise applications in several frontier electronic devices that make use of novel computing vectors. Here a study is presented of δ‐Sr x V 2 O 5 , expanded δ‐Sr x V 2 O 5 , exfoliated δ‐Sr x V 2 O 5 and δ‐K x V 2 O 5 using a combination of synchrotron soft X‐ray spectroscopy and density functional theory calculations. The band gaps of each system are experimentally determined, and their calculated electronic structures are discussed from the perspective of the measured spectra. Band gaps ranging from 0.66 ± 0.20 to 2.32 ± 0.20 eV are found, and linked to the underlying structure of each material. This demonstrates that the band gap of V 2 O 5 can be tuned across a large portion of the range of greatest interest for device applications. The potential for metal–insulator transitions, tuneable electron correlations and charge ordering in these systems is discussed within the framework of our measurements and calculations, while highlighting the structure‐property relationships that underpin them.