【摘要】 采用第一性原理计算了FeTe0.5Se0.5在两种不同结构模型下的电子结构、晶格动力学以及电声子相互作用.结果表明:用两种结构模型计算得到的电子结构大致相同,费米面附近的态密度主要来自Fe d电子的贡献.对两种模型我们根据不可约表示分析了Γ点的光学模频率,并给出了声子谱及声子态密度.用模型1和模型2计算得到的电声子耦合常数λ分别为0.20和0.22,都非常弱,无法解释实验上较高的超导转变温度.因此,超导材料FeTe0.5Se0.5和其他的铁基超导材料一样,都不属于常规的电声子耦合超导材料.更多还原

【Abstract】 The electronic structure,lattice dynamics and electron-phonon interaction of FeTe0.5Se0.5 in two different structural models are investigated by using the first-principles.The results show that the electronic structures of the two structural models are similar to each other,and the electronic density of states near the Fermi level comes mainly from Fe d electrons.For both two models,we analyze the optical modes at the Γ point based on irreducible representation,and give the phonon spectra and the phonon density of the states.The electron-phonon coupling coefficients λ calculated by model 1 and model 2 are 0.20 and 0.22,respectively,which are both too small to explain the high superconducting transition temperature discovered in experiment.Therefore,we think that superconducting material FeTe0.5Se0.5 doesn ’ t belong to the conventional electron-phonon coupling mechanism,which is similar to the other Fe-based superconducting materials.更多还原