期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：36
页码：15708-15711
DOI：10.1073/pnas.1007354107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Motivated by the potential high-temperature superconductivity in hydrogen-rich materials, the high-pressure structures of SiH4(H2)2 in the pressure range 50-300 GPa were extensively explored by using a genetic algorithm. An intriguing layered orthorhombic (Ccca) structure was revealed to be energetically stable above 248 GPa with the inclusion of zero-point energy. The Ccca structure is metallic and composed of hydrogen shared SiH8 dodecahedra layers intercalated by orientationally ordered molecular H2. Application of the Allen-Dynes modified McMillan equation yields remarkably high superconducting temperatures of 98-107 K at 250 GPa, among the highest values reported so far for phonon-mediated superconductors. Analysis reveals a unique superconducting mechanism that the direct interactions between H2 and SiH4 molecules at high pressure play the major role in the high superconductivity, while the contribution from H2 vibrons is minor.
