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Author Molen, S. J. van der ♦ Nagengast, D. G. ♦ Gogh, A. T. M. van ♦ Kalkman, J. ♦ Kooij, E. S. ♦ Rector, J. H. ♦ Griessen, R.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword MATERIALS SCIENCE ♦ ALLOYS ♦ CONFINEMENT ♦ CRYSTAL STRUCTURE ♦ ELECTRICAL PROPERTIES ♦ HYDROGENATION ♦ MIRRORS
Abstract We study the structural, optical, and electrical properties of Mg{sub z}Y{sub 1{minus}z} switchable mirrors upon hydrogenation. It is found that the alloys disproportionate into essentially pure YH{sub 3{minus}{delta}} and MgH{sub 2} with the crystal structure of YH{sub 3{minus}{delta}} dependent on the Mg concentration z. For 0{lt}z{lt}0.1, both hcp and fcc YH{sub 3{minus}{delta}} are observed, whereas for z{ge}0.1 only cubic YH{sub 3{minus}{delta}} is present. Interestingly, cubic YH{sub 3{minus}{delta}} is expanded compared to YH{sub 2}, in disagreement with theoretical predictions. From optical and electrical measurements we conclude that cubic YH{sub 3{minus}{delta}} is a transparent insulator with properties similar to hexagonal YH{sub 3{minus}{delta}}. Our results are inconsistent with calculations predicting fcc YH{sub 3{minus}{delta}} to be metallic, but they are in good agreement with recent GW calculations on both hcp and fcc YH{sub 3}. Finally, we find an increase in the effective band gap of the hydrided Mg{sub z}Y{sub 1{minus}z} alloys with increasing z. Possibly this is due to quantum confinement effects in the small YH{sub 3} clusters.
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-06-15
Publisher Place United States
Journal Physical Review B
Volume Number 63
Issue Number 23


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