Han Yanfeng, Dai Yongbing, Shu Da, Wang Jun, Sun Baode
State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, People's Republic of China.
J Phys Condens Matter. 2006 May 3;18(17):4197-205. doi: 10.1088/0953-8984/18/17/008. Epub 2006 Apr 13.
The TiB(2)(0001) surfaces are calculated using the first-principles total-energy plane-wave pseudopotential method based on density functional theory. It is found that there are large relaxations within the top three layers for both termination surfaces, and the outermost and second interlayer relaxations for B-terminated surfaces are much larger than those for Ti-terminated surfaces. The charge depletion in the vacuum and the charge accumulations in the interlayer region between the first and second layers reinforces the interlayer Ti-B chemical bonds and reduces the outermost interlayer distance. Simultaneously, the charge accumulation for B-terminated surface is more than that for Ti-terminated surface, and the interlayer Ti-B bonds between the second and third layers are weakened more for the B-terminated surface. The Ti-terminated surface is thermodynamically more favourable in most of the range of μ(B)(slab).
基于密度泛函理论，采用第一性原理全能量平面波赝势方法计算了TiB₂(0001)表面。结果发现，两种终止表面的前三层内都有较大的弛豫，且B终止表面的最外层和第二层间弛豫比Ti终止表面的大得多。真空中的电荷耗尽以及第一层和第二层之间的层间区域中的电荷积累增强了层间Ti-B化学键，并减小了最外层的层间距离。同时，B终止表面的电荷积累比Ti终止表面的多，且B终止表面第二层和第三层之间的层间Ti-B键减弱得更多。在μ(B)(平板)的大部分范围内，Ti终止表面在热力学上更有利。
