First principles calculations of the effect of tension of MgB2 film on its superconductivity

Abstract

摘要 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 关键词: 超导电性 / 能带结构 / 声子频率 / 电声子耦合 Abstract Using the full-potential linear-muffin-tin-orbital programs and the linear-response linear-muffin-tin-orbital programs，we calculated the electronic band structure, phonon spectrum and electron-phonon coupling strength in MgB2 film, and studied the effect of tension of MgB2 film on its superconductivity. It is shown that the softening of E2g phonon frequency, enchancement of the electron-phonon coupling and the phonon logarithm average frequency with contraction of the lattice constant along c-axis and elongation along a-axis resulted in the increase of superconducting transition temperature Tc. Our results are in good agreement with corresponding experiment. Keywords: superconductivity / electronic band structure / phonon frequency / electron-phonon coupling 作者及机构信息 舒华兵, 刘 甦, 马 荣, 刘 楣 基金项目: 国家自然科学基金(批准号:10574021)和高等学校博士学科点专项科研基金(批准号:20060286044)资助的课题. Authors and contacts 参考文献 施引文献