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|Title:||Defect levels and hyperfine constants of hydrogen in beryllium oxide from hybrid-functional calculations and muonium spectroscopy|
|Authors:||Marinopoulos, A. G.|
Vilão, R. C.
Vieira, R. B. L.
Alberto, H. V.
Gil, J. M.
Yakushev, M. V.
|Publisher:||Taylor and Francis Ltd.|
|Citation:||Defect levels and hyperfine constants of hydrogen in beryllium oxide from hybrid-functional calculations and muonium spectroscopy / A. G. Marinopoulos, R. C. Vilão, R. B. L. Vieira, et al. — DOI 10.1080/14786435.2017.1328133 // Philosophical Magazine. — 2017. — Vol. 97. — Iss. 24. — P. 2108-2128.|
|Abstract:||The atomistic and electronic structures of isolated hydrogen states in BeO were studied by ab initio calculations and muonium spectroscopy ((Formula presented.) SR). Whereas standard density-functional theory with a semi-local GGA functional led to a detailed probing of all possible minimum-energy configurations of hydrogen further calculations with the hybrid HSE06 functional provided improved properties avoiding band-gap and self-interaction errors. Similarly to earlier findings for the other wide-gap alkaline-earth oxide, MgO, hydrogen in BeO is also predicted to be an amphoteric defect with the pinning level, E((Formula presented.)), positioned in the mid-gap region. Both donor and acceptor levels were found too deep in the gap to allow for hydrogen to act as a source of free carriers. Whereas, hydrogen in its positively-charged state, (Formula presented.), adopts exclusively hydroxide-bond OH configurations, (Formula presented.) and (Formula presented.) instead show a preference to occupy cage-like interstitial sites in the lattice. (Formula presented.) in particular displays a multitude of minimum-energy configurations: its lowest-energy ground state resembles closely a trapped-atom state with a nearly spherical spin-density profile. In contrast to the strongly ionic MgO, (Formula presented.) in BeO was further found to stabilise in additional higher-energy elongated-bond OH configurations whose existence should be traced to a partial covalent character of the Be–O bonding. Calculations of the proton-electron hyperfine coupling for all (Formula presented.) states showed that the ground-state interstitial (Formula presented.) configuration is dominated by an isotropic hyperfine interaction with a magnitude very close to the vacuum value, a finding corroborated by the (Formula presented.) SR-spectroscopy data. © 2017 Informa UK Limited, trading as Taylor & Francis Group.|
|Keywords:||AB INITIO CALCULATIONS|
ALKALINE EARTH METALS
AB INITIO CALCULATIONS
ALKALINE EARTH OXIDES
MINIMUM ENERGY CONFIGURATION
DENSITY FUNCTIONAL THEORY
|Appears in Collections:||Научные публикации, проиндексированные в SCOPUS и WoS CC|
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