( 北京理工大學(xué) 國(guó)家高技術(shù)綠色材料發(fā)展中心， 北京 100081)
摘 要: 采用總體能量-平面波贗勢(shì)方法， 并結(jié)合超軟贗勢(shì)技術(shù)， 計(jì)算了金屬La、 Ni及合金LaNi5的總體能量、 能帶結(jié)構(gòu)、 電子態(tài)密度以及Mulliken布居值。 根據(jù)計(jì)算結(jié)果， 分析了La、 Ni和LaNi5的電子結(jié)構(gòu)。 結(jié)果表明： 形成合金后費(fèi)米面能量位置漂移， 介于Ni和La的費(fèi)米面之間， 費(fèi)米面上主要是Ni 3d電子； 費(fèi)米面附近導(dǎo)帶的電子結(jié)構(gòu)變化較大； 合金中La和Ni間存在電子轉(zhuǎn)移， 形成了弱的La—Ni鍵， 且?guī)Р糠蛛x子性； 與純金屬相比， 形成合金后La的穩(wěn)定性增強(qiáng)， 而Ni的穩(wěn)定性減弱。 計(jì)算了LaNi5的理論生成熱， 結(jié)果能較好地符合實(shí)驗(yàn)值。
關(guān)鍵字: LaNi5; 總體能量; 生成熱; 電子結(jié)構(gòu)
（ National Development Center of Hi-Tech Green Materials,
Beijing Institute of Technology, Beijing 100081, China）
Abstract: The calculations of total energy, energy band structure, electronic density of states and Mulliken population of LaNi5 were performed by adopting the method of total energy combined with ultra-soft Pseudopotential technology. The change of the electronic structure in the formation of LaNi5 was analyzed according to the calculations. The results show that the Fermi level shifts toward the position between those of La and Ni. Ni 3d electrons mainly contribute to the states of density at Fermi level. The electronic structure of conduction band near Fermi level is changed markedly, especially for Ni. In alloys, electron transfer exists between La and Ni, thus weakly bond is formed with partly of ionicity. The stability of La increases and that of Ni decreases in LaNi5 compared with the pure metal. The theoretical formation heat of LaNi5 is obtained and accords well with the experimental value.
Key words: LaNi5; total energy; formation heat; electronic structure
