Oxygen adsorption behavior on MoSi_2(001)surface

Using first-principles method,surface energy of MoSi_2 surfaces is calculated firstly,MoSi_2 (001) Si-|-Si plane with lower surface energy is preferred cleavage plane;single oxygen atom,double oxygen atoms,and oxygen molecule adsorption behaviors on MoSi_2(001) Si-|-Si surface are studied by formation energy and population analysis.The structure with single oxygen atom layered at the hollow position is more stable.After single oxygen atom adsorbs at the hollow position,single oxygen atom has a strong selective interaction with Si,and the Si-O bond length and bond angle are closed to those of SiO_2,indicating that O in low concentration is likely to combine with Si to generate SiO_2.When double oxygen atoms absorb on top-and-hollow position,besides the strong interaction between O and Si atoms,there also exists interaction between Mo and O.O_2 may be most likely to approach hollow position of MoSi_2(001) surface by the parallel way,and decompose into oxygen atoms,then absorb on hollow position by oxygen atom form.