Calculation of elastic strain and electronic effects on surface segregation.
Calculation of elastic strain and electronic effects on surface segregation.
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DOI：
10.1103/physrevb.32.5051
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发表时间：
1985-10
期刊：
影响因子：
--
通讯作者：
Tománek;Aligia;Balseiro
中科院分区：
文献类型：
--
作者：
Tománek;Aligia;Balseiro
我们提出了一种计算金属表面杂质偏析热的电子理论，同时考虑了电子对表面能的贡献和尺寸不匹配能。总能量的吸引部分用多波段紧密结合的哈特里哈密顿量来描述，而排斥部分则假设玻恩-迈尔型原子间排斥，这可能取决于电荷转移。通过简化态密度和电荷转移的假设，可以由只依赖于合金组分的体黏结能、体模量和原子尺寸的表达式得到偏析热和平衡几何。利用这一理论，我们计算了Rh、Cu和Au杂质在不同Pt单晶表面上的偏析热，并与已有实验数据进行了比较。
We present an electronic theory for calculating the heat of impurity segregation at metal surfaces by considering both the electronic contribution to the surface energy and the size-mismatch energy. The attractive part of the total energy is described by a multiband tight-binding Hartree Hamiltonian, and for the repulsive part Born-Mayer-type interatomic repulsions are assumed, which may depend on charge transfer. With simplifying assumptions about the density of states and the charge transfer, the heat of segregation and the equilibrium geometry can be obtained from an expression which depends only on the bulk cohesive energy, the bulk modulus, and the atomic size of the alloy components. Using this theory, we calculate the heat of segregation of Rh, Cu, and Au impurities on different Pt single-crystal surfaces and make a comparison with existing experimental data.