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通过第一性原理赝势平面波方法研究了氧在Nb(110)表面的吸附性质随覆盖度变化规律.O在Nb(110)表面最稳定吸附位是洞位,次稳定吸附位是长桥位.在长桥位吸附时,O诱导Nb(110)表面功函数随覆盖度的增加而几乎线性增加;但当O在洞位吸附时,与干净Nb表面相比,覆盖度为0.75 ML和1.0 ML时功函数增加,而覆盖度为0.25 ML和0.5 ML时功函数减小.通过对面平均电荷密度分布和偶极矩变化的讨论,解释了由吸附导致功函数复杂变化的原因.通过对表面原子结构和态密度分析,讨论了O在Nb表面吸附时引起表面原子结构变化以及O和Nb(110)表面原子的相互作用.
The first-principle pseudopotential plane wave method was used to study the variation of adsorption properties of oxygen on the surface of Nb (110) with the change of coverage.O was the most stable adsorption site on the surface of Nb (110) At the long bridge sites, the O induced Nb (110) surface work function almost linearly increased with the increase of coverage, but when O was adsorbed on the hole, the coverage was 0.75 ML and 1.0 compared with the clean Nb surface ML, the work function increases while the work function decreases with the coverage of 0.25 ML and 0.5 ML.The reason of complex work function changes caused by adsorption is explained by the discussion of the average surface charge density distribution and the change of dipole moment.Through the analysis of the surface Atomic structure and density of states, we discuss the change of surface atomic structure and the interaction between O and Nb (110) atoms when O is adsorbed on Nb surface.