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应用全势线性响应线性糕模轨道方法计算MgB2的电子能带结构、声子谱及电声子耦合常数,并讨论MgB2的超导电性.通过比较MgB2薄膜双轴拉伸前后超导电性的变化可以看出,随着a轴晶格常数增大和c轴晶格常数减小,声子谱中硼的E2g声子频率显著下降,使得电声子耦合强度λ和声子对数平均频率ωln增强,提高了MgB2薄膜的超导转变温度.理论计算结果与文献中的实验测量结果相符.
The electron band structure, phonon spectrum and electro-phonon coupling constants of MgB2 were calculated by the full potential linear response linear cake-orbit method, and the superconductivity of MgB2 was discussed. By comparing the changes of superconductivity before and after MgB2 film biaxial stretching It can be seen that as the a-lattice lattice constant increases and the c-axis lattice constant decreases, the phonon frequency of boron in the phonon spectrum decreases significantly, making the electro phonon coupling intensity λ and phonon logarithmic average frequency ωln enhanced , Which improves the superconducting transition temperature of MgB2 films.The theoretical calculation results are consistent with the experimental results in the literature.