物理
从头算
结晶学
曲面(拓扑)
材料科学
几何学
量子力学
化学
数学
作者
Henry P. Pinto,Risto M. Nieminen,Simon D. Elliott
出处
期刊:Physical Review B
[American Physical Society]
日期:2004-09-03
卷期号:70 (12)
被引量:201
标识
DOI:10.1103/physrevb.70.125402
摘要
Starting from the theoretical prediction of the $\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ structure using density-functional theory in the generalized gradient approximation, we have studied the (1 1 1), (0 0 1), (1 1 0), and (1 5 0) surfaces. The surface energies and their corresponding structures are computed and compared with predictions for (0 0 0 1) $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ and available experimental results for $\ensuremath{\gamma}$-alumina surfaces. (1 1 1) and (0 0 1) surfaces are predicted to be equally stable, but to show quite different structure and reactivity. Whereas a low coverage of highly reactive trigonal Al occurs on (1 1 1), (0 0 1) exhibits a more dense plane of both five-coordinate and tetrahedral Al. Microfaceting of a (1 1 0) surface into (1 1 1)-like planes is also observed. The implications for the structure of ultrathin dielectric films and for the surfaces of disordered transition aluminas are discussed.
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