中文摘要：

采用基于第一性原理的密度泛函方法对Si（001）-p（2×2）表面的原子结构和电子态进行了系统的研究。计算采用的是含有8个Si原子层的超晶胞结构，且电子态是由Si（001）-p（2×2）表面的优化结构分析所得。计算结果表明表面形成了非对称二聚体，近表面几层原子发生相应的弛豫现象。由于表面原子的配位环境发生变化，表面原子的电荷分布也发生了变化。通过对比，得到了与实验结果一致的计算结果。

英文摘要：

The surface atomic structure and electronic states of the Si（001）-p（2×2） surface have been investi- gated by using the first-principle method. The calculations are performed using a supercell consisting of eight surface layers of Si, and the electronic states are determined based on the optimized geometric structure of p（2 ×2）. The cal culated results show that the asymmetric dimmers form on the outmost surface, and the corresponding displacements of several surface atoms are observed. With the bonding conditions altering, the charges transfer between the atoms on the surface. It is found that the calculated results agree with the available experimental data and the previous calcula tions well.