STABILITY OF IONIC-CRYSTAL SURFACES
STABILITY OF IONIC-CRYSTAL SURFACES
复制标题
DOI：
10.1088/0022-3719/12/22/036
复制
发表时间：
1979-01-01
期刊：
影响因子：
--
通讯作者：
TASKER, PW
中科院分区：
文献类型：
--
作者：
TASKER, PW
当离子晶体中垂直于表面的重复单元中存在偶极矩时，静电能中的晶格和发散，计算的表面能为无穷大。证明了这种发散的原因，并将任何离子或部分离子材料的表面分为三种类型。类型1是中性的，每个平面上的阴阳离子数量相等，类型2带电，但由于对称的堆积顺序，没有垂直于表面的偶极矩。这两个表面都应该具有适度的表面能量，并且可能是稳定的，表面区域的离子只有有限的松弛。类型3的表面带电，并且在垂直于该表面的重复单元中具有偶极矩。这个表面只有通过实质性的重建才能稳定下来。这些结论对分析离子晶体的表面结构具有重要意义。
When there is a dipole moment in the repeat unit perpendicular to the surface in an ionic crystal, lattice sums in the electrostatic energy diverge and the calculated surface energy is infinite. The cause of this divergence is demonstrated and the surfaces of any ionic or partly ionic material are classified into three types. Type 1 is neutral with equal numbers of anions and cations on each plane and type 2 is charged but there is no dipole moment perpendicular to the surface because of the symmetrical stacking sequence. Both these surfaces should have modest surface energies and may be stable with only limited relaxations of the ions in the surface region. The type 3 surface is charged and has a dipole moment in the repeat unit perpendicular to the surface. This surface can only be stabilised by substantial reconstruction. These conclusions are important for the analysis of the surface structure of ionic crystals.