Barth Clemens, Henry Claude R
CRMCN-CNRS, Campus de Luminy, case 913, 13288 Marseille Cedex 09, France.
Phys Rev Lett. 2007 Mar 30;98(13):136804. doi: 10.1103/PhysRevLett.98.136804.
In this Letter we consider the surface double layer on (001) surfaces of UHV cleaved and annealed alkali halide crystals (KCl, NaCl), which we studied with dynamic scanning force microscopy and Kelvin probe force microscopy. Kelvin images show bright and round patches at corner sites and steps. Images with atomic resolution always show kinks at the latter step sites. Our findings are in perfect agreement with the long-standing picture that, due to the presence of divalent impurity ions, the surface carries a net negative surface charge originating from negative cation vacancies at kinks.
在本信函中，我们研究了超高真空（UHV）中解理和退火后的碱金属卤化物晶体（KCl、NaCl）（001）表面上的表面双层，采用了动态扫描力显微镜和开尔文探针力显微镜进行研究。开尔文图像显示在角位和台阶处有明亮的圆形斑块。具有原子分辨率的图像总是显示在后者的台阶位置有扭折。我们的发现与长期以来的观点完全一致，即由于二价杂质离子的存在，表面带有源自扭折处负阳离子空位的净负表面电荷。
