利用基于密度泛函理论的第一性原理方法， NiAs与PbO型FeX（ X＝S， Se， Te）结构的稳定性与电子特征得到了研究.计算结果显示Fe的内聚能与X－Fe元素之间的相互作用是影响FeX结构稳定性的重要因素.当X原子半径较小、电负性较大时（ X＝S）， FeX趋向于形成Fe－X相互作用较强、密度较大的NiAs型结构；当X原子半径较大、电负性较小时（ X＝Se， Te）， FeX趋向于形成Fe－Fe相互作用较强、密度较小的PbO型结构.此外，压强使得PbO型FeX结构的稳定性降低.当压强分别大于5、9 GPa时， FeTe、FeSe趋向于形成NiAs型结构.PbO型FeSe中Fe原子周围的电子密度随压强的增大而增大.%The structural stabilities and electronic properties of PbO-and NiAs-type FeX ( X=S, Se, Te) were investigated within density functional theory.The calculated results showed that the cohesive energy of Fe atoms and the interactions between Fe and X ( X=S, Se, Te) elements played important roles in the structural stabili-ties of FeX.For X atoms with smaller radius and higher electronegativity , such as S , FeX preferred to NiAs-type structure which had higher Fe-X bond energy and density than PbO-type structure.On the other hand , when the X atomic radius was larger and its electronegativity was lower , such as Se and Te , the PbO-type structure for FeX was more stable than NiAs-type structure.The PbO-type FeX had higher Fe-Fe bond energy and lower density.In further , it was found that the pressure would decrease the structural stability of PbO-type FeX and make FeSe and FeTe prefer to NiAs-type structure at 9 and 5 GPa, respectively.For PbO-type FeSe, the electronic density around Fe atoms increased with the increasing of pressure.
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