(中南大學(xué) 材料科學(xué)與工程學(xué)院 有色金屬材料科學(xué)與工程教育部重點(diǎn)實驗室，長沙 410083)
摘 要: 采用第一原理贗勢平面波方法，計算鋁晶體學(xué)自由表面(100)、(110)和(111)的能量、幾何與電子結(jié)構(gòu)。根據(jù)表面能計算預(yù)測鋁自由表面結(jié)構(gòu)的穩(wěn)定性。結(jié)果表明：鋁自由表面結(jié)構(gòu)穩(wěn)定性由強(qiáng)到弱的順序為(111)、(100)、(110)；表面原子馳豫不僅引起表面幾何結(jié)構(gòu)的變化，而且使表面層的電子結(jié)構(gòu)與鍵合特性發(fā)生改變；(100)、(110)和(111)表層馳豫分別為3.337%、−6.147%和−2.364%；表面電荷密度不同引起表面能差異，表面原子層和次表面原子層的電荷面密度在s和p軌道上重新分布；表面原子層電荷密度越大，表面能越低。
關(guān)鍵字: Al晶體；第一原理；表面馳豫；表面能
（Key Laboratory of Non-ferrous Metal Materials Science and Engineering, Ministry of Education, School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The surface energy, atomic geometry and electronic structures of Al(100), (110) and (111) free surfaces were calculated using the method of supercell and the first-principles pseudopotential plane waves within generalized gradient approximation. According to the calculated surface energy, the structural stability of Al free surfaces from strong to weak is predicted in the order as (111), (100) and (110). The relaxation of the surface atom layers not only causes the change of geometrical structures of the surface models, but also leads to the variation of their electronic structures and bonding characters. For the (100), (110) and (111) free surfaces, the calculated surfaces relaxation are 3.337%, −6.147% and −2.364%, respectively. The surface energy is related to the surface electron density distribution, the electron density of orbital s and p of the first two surface atom layers redistributes. The higher the surface electron density is, the lower the surface energy is.
Key words: aluminum crystal; first principle; surface relaxation; surface energy
