中文摘要：

采用密度范函理论计算了金属化合物MgB2（001）薄膜结构的电子能带结构和状态密度,计算的交换相关能分别采用LDA和GGA。规范保守赝势的计算结果表明,晶格常数与实验值误差在很小的范围内,分析了引起MgB2（001）面结构超导转变时电子浓度和偏态密度的变化情况,发现构成该超导体结构的成键有三种,着重从结构的电子浓度变化分析了其超导特性,六角蜂窝状结构中硼原子间相互作用为sp^2杂化的共价键,镁原子和硼原子之间是离子键结合,镁原子层是金属键结合,镁原子的价电子部分转移到硼原子的pz轨道,部分电子为镁原子层共用。MgB2的超导机制为强烈的电子-声子耦合,为B原子间强烈的共价作用形成,是传统S波超导体。对Mg元素同一主族的其它硼化物进行布居分析,发现MgB2中Mg原子电子转移明显强于BeB2和CaB2,说明电子浓度是引起超导转变的一个重要因素。

英文摘要：

Both GGA and LDA are applied to calculate the band structure and DOS of MgB2 （001） , the ionic ＂core＂ is represented by Pseudo potential. Crystal constants are in close with other experiment results. Three kinds of chemical bonds exist among Mg and B atoms, between magnesium and boride is ionic bond and metallic bond is the predominant interaction in the layer formed by magnesium atoms. A strong covalent bond in the form of sp^2 hybrid between boride atoms is the most important factor which could affect the transition temperature of MgB2. Population analysis clearly shows that electrons are transferred from Mg to B , as a result , phonon - electron coupling in the layer of B is very strong . We also clarified the electron populations of BeB2 and CaB2 and compared the results among them, the electron transfer between metallic atom and B is mostly obvious in MgB2.