【摘要】 采用遗传算法与第一性原理相结合的计算方法对富金的Au3Si体系进行全局结构搜索,最低能量结构是一对称性为Amm2空间群的Au6Si2晶胞,且验证了其稳定性,并将其与Au、Si单相结构的性质进行比较研究。态密度和能带计算结果表明,Au6Si2结构中Si的p轨道电子和Au的d轨道电子发生杂化,导致p轨道电子的能级降低,使得能带结构没有带隙。热力学性质显示该Au6Si2结构的熵大于Au和Si单相晶体结构的熵,有存在的可能性。更多还原

【Abstract】 The stable crystal structure of Au-rich Au3 Si systems was predicted using agenetic algorithm in combination with first-principles calculations.The results show that the lowest-energy structure is an Au6Si2 cell with space group Amm2.The newly discovered structure is further shown to be energetically stable.The properties of Au6Si2 crystal were compared with single phases of pure Au and pure Si.Density of States and band structure show that the d electrons of Au atom hybridize with the p electrons of Si atom,lowering the p electron’s energy level,reducing the band gap and even vanishing.The Au6Si2 crystal can exist thermodynamically due to its larger entropy than that of pure Au or pure Si phase.更多还原