吸附O的Cu(110)c(2×1)表面原子结构和电子态

采用第一性原理的密度泛函理论方法计算了清洁Cu(110)表面和吸附O原子的Cu(110) c(2×1)表面的原子结构, 结构弛豫和电子结构, 得到了各种表面结构参数. 分别计算了O原子在Cu(110)表面三个可能吸附位置吸附后的能量, 并给出了能量最低的吸附位置上各层原子的弛豫特性和态密度. 结果表明O吸附后的Cu(110)表面有附加列(added-row)再构的特性, O原子吸附在最表层铜原子上方, 与衬底Cu原子的垂直距离为0.016 nm, 以氧分子为能量基准的吸附能为－1.94 eV; 同时由于Cu 3d- O 2p态的杂化作用使得低于费米能级5.5~6.0 eV的范围内出现了局域的表面态. 计算得到清洁的和氧吸附的Cu(110)表面的功函数分别为4.51 eV和4.68 eV. 电子态密度的结果表明：在Cu(110) c(2×1) 表面O吸附的结构下, 吸附O原子和金属衬底之间的结合主要是由于最表层Cu原子3d态和O原子2p态的相互作用.

The Atomic Structure and Electronic States of Oxygen-adsorbed on Cu(110) c(2×1) Surface

The surface atomic geometry, structural relaxations, and electronic states of clean Cu(110) surface and oxygen-adsorbed Cu(110) c(2×1) surface have been studied by using ab initio total energy calculations. The density functional calculations have been carried out for three possible adsorbed positions of oxygen and the most favorable one has been determined by total energy comparison. It reveals that the added-row reconstruction is the most stable one with maximum adsorption energy in Cu(110) c(2×1) surface and the adsorbed oxygen atom is beyond the outmost surface Cu layer slightly. The adsorbates lie approximately 0.016 nm above the outermost Cu layer and the hybridized band derived from Cu 3d-O 2p hybridization locates in the range of －5.5～－6.0 eV below Fermi energy. The adsorption energy of oxygen in this configuration is determined to be －1.94 eV with respect to oxygen molecule. The work functions of clean Cu(110) and oxygen-adsorbed Cu(110) c(2×1) surface are calculated to be 4.51 eV and 4.68 eV, respectively. The surface electronic structures show that the cohesive effect between adsorbates and the substrate Cu atoms is essentially due to the Cu 3d- O 2p interaction.