Theoretical study of segregation of Zn and Pd in Pd-Zn alloys

被引：53

作者：

Chen, ZX ^{[1
]}

Neyman, KM ^{[1
]}

Rösch, N ^{[1
]}

机构：

[1] Tech Univ Munich, Inst Phys & Theoret Chem, D-85747 Garching, Germany

来源：

SURFACE SCIENCE | 2004年 / 548卷 / 1-3期

关键词：

density functional calculations; surface segregation; palladium; zinc; alloys;

D O I：

10.1016/j.susc.2003.11.018

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Surface segregation of Zn and Pd in PdZn alloys was investigated based on density functional calculations using periodic slab models. The segregation propensity of Pd-Zn films was found to be support-dependent: Zn showed a stronger propensity to segregate on Zn support than on Pd support; likewise, for Pd the propensity was stronger on Pd support than on Zn support. In self-supported 1:1 alloy films, segregation of neither Zn nor Pd was favorable. Segregation was suppressed due to the fact that Pd-Zn heteronuclear bonds are stronger than the corresponding homo-nuclear bonds Pd-Pd and Zn-Zn. However, in films rich in Zn or Pd, segregation of the dominant component was possible. For instance, when a monolayer of Pd is deposited on a Zn(0 0 0 1) film, segregation of Zn is calculated energetically favorable, in agreement with experimental observations. With increasing Zn concentration in the top surface layer, the corrugation of alloy films was reduced. (C) 2003 Published by Elsevier B.V.

引用

页码：291 / 300

页数：10

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