二十面体AlPd Mn准晶近似相的电子结构研究

Study of Electronic Structures of Icosahedral AlPd Mn Quasicrystalline Approximant

基于二十面体AlPdMn准晶近似相的Quandt-Elser结构模型,使用VASP第一性原理计算程序包,计算了二十面体AlPdMn准晶近似相的电子态密度NE和电荷密度.计算结果表明,i-AlPdMn准晶近似相的DOS曲线上,在Fermi能EF附近形成了一个宽度约为1 eV的很深的赝能隙;Mn的d峰被宽化,并出现在能量较低的位置上;价电子被局域在Al—Mn,Al—Pd,Al—Al,Mn—Pd之间的中间区域,具有共价键的特征,且Al—Mn间的共价键最强.赝能隙的形成和化合键的共价键特征可以很好地解释i-AlPdMn准晶和准晶近似相的特殊物理性质.

Based on Quandt-Elser structural model of icosahedral AlPdMn quasicrystalline approximant, and by using the ab-initio computation package VASP, the electronic density of state （DOS） and the charge density of i-AlPdMn approximant were calculated. The results show that a deep pseudogap with a width of about 1 eV exists at the Fermi level in the DOS curvet the Mn d peak is widened and locates at a lower energy; the valence electrons are localized at the middle of Al-Mn, Al-Pd, Al-Al atomic pairs, which shows covalent bonding character; the bond of Al-Mn is the strongest. With the pseudogap and the covalent bonding characteristics the special physical properties of i-AlPdMn quasicrystal and approximant can be well explained.