ABSTRACT Ab initio pseudopotential calculations have been conducted for the superconducting filled skutterudite compounds BaPt Ge , SrPt Ge , and ThPt Ge in order to explore the effect of spin–orbit interaction(SOI) by using the planewave pseudopotential method and the density functional theory. The electronic structure calculations suggest that the density of states at the Fermi level is dominated by Ge atom's p states, with the guest atoms (Ba, Sr, or Th) making very little or no contribution. However, when the SOI is included, the phonon frequencies of BaPt Ge and SrPt Ge are hardened, which in turn decreases the electron–phonon interaction. By integrating the Eliashberg spectral function F(ω) with SOI included, the average electron–phonon coupling parameters are found to be 0.74 for BaPt Ge , 0.79 for SrPt Ge , and 0.69 for ThPt Ge . Using a reasonable value of = 0.10 for the effective Coulomb repulsion parameter, the superconducting critical temperature is found to be 5.36 K for BaPt Ge , 5.43 K for SrPt Ge , and 4.45 K for ThPt Ge with SOI. These values are in excellent accordance with their reported experimental values of 5.35 K, 5.4 K and 4.62 K.

中文翻译：

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自旋轨道相互作用对填充方钴矿 MPt4Ge12(M=Ba, Sr and Th) 超导性的影响

摘要 为了利用平面波赝势法和密度泛函理论探索自旋轨道相互作用（SOI）的影响，对超导填充方钴矿化合物 BaPt Ge、SrPt Ge 和 ThPt Ge 进行了从头算赝势计算。电子结构计算表明，费米能级的态密度由 Ge 原子的 p 态主导，客体原子（Ba、Sr 或 Th）贡献很小或没有贡献。然而，当包含 SOI 时，BaPt Ge 和 SrPt Ge 的声子频率会变硬，从而降低电子-声子相互作用。通过对包含 SOI 的 Eliashberg 谱函数 F(ω) 进行积分，发现 BaPt Ge 的平均电子-声子耦合参数为 0.74，SrPt Ge 为 0.79，ThPt Ge 为 0.69。使用 = 0.10 的有效库仑排斥参数的合理值，发现 BaPt Ge 的超导临界温度为 5.36 K，SrPt Ge 为 5.43 K，ThPt Ge 与 SOI 的超导临界温度为 4.45 K。这些值非常符合他们报告的 5.35 K、5.4 K 和 4.62 K 的实验值。