Connétable D, Timoshevskii V, Masenelli B, Beille J, Marcus J, Barbara B, Saitta A M, Rignanese G-M, Mélinon P, Yamanaka S, Blase X
LPMCN, Université Claude Bernard Lyon I and CNRS, UMR 5586, Bâtiment Brillouin, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
Phys Rev Lett. 2003 Dec 12;91(24):247001. doi: 10.1103/PhysRevLett.91.247001. Epub 2003 Dec 8.
We present a joint experimental and theoretical study of the superconductivity in doped silicon clathrates. The critical temperature in Ba(8)@Si-46 is shown to strongly decrease with applied pressure. These results are corroborated by ab initio calculations using MacMillan's formulation of the BCS theory with the electron-phonon coupling constant lambda calculated from perturbative density functional theory. Further, the study of I(8)@Si-46 and of gedanken pure silicon diamond and clathrate phases doped within a rigid-band approach show that the superconductivity is an intrinsic property of the sp(3) silicon network. As a consequence, carbon clathrates are predicted to yield large critical temperatures with an effective electron-phonon interaction much larger than in C60.
我们展示了对掺杂硅笼合物中超导电性的联合实验和理论研究。结果表明，Ba(8)@Si-46中的临界温度随外加压力而显著降低。这些结果通过使用麦克米兰形式的BCS理论进行的从头算计算得到了证实，其中电子-声子耦合常数λ是根据微扰密度泛函理论计算得出的。此外，对I(8)@Si-46以及在刚性带方法中掺杂的假想纯硅金刚石和笼合物相的研究表明，超导电性是sp(3)硅网络的固有属性。因此，预计碳笼合物将产生比C60中有效电子-声子相互作用大得多的临界温度。
