Superconductivity of Metal Deficient Silicon Clathrate Compounds, Ba8-xSi46 (0 < x ≤ 1.4)
- 3 April 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 42 (9) , 2933-2937
- https://doi.org/10.1021/ic020676q
Abstract
Single crystals of the Ba-containing silicon clathrate superconductor Ba(7.76)Si(46) were prepared using a high-pressure and high-temperature condition (3 GPa, 1300 degrees C). It crystallized in the cubic space group Pm-3n with a = 10.3141(7) A and Z = 1. There are two crystallographically different types of Ba sites, at the centers of Si dodecahederal (Ba@Si(20)) and Si tetrakaidecahedral (Ba@Si(24)) cages. On evacuation at 527 degrees C, a part of Ba atoms were removed from the Ba@Si(20) sites. The superconducting transition temperature (T(c)) decreased from 9.0 to 6.0 K with the decrease of the Ba content from 7.76 to 6.63 Ba/Si(46). The Ba deficient sites and the deficiency were determined by the structural refinement in the single-crystal X-ray analyses.Keywords
This publication has 22 references indexed in Scilit:
- Superconductivity in the Filled Cage Compounds andPhysical Review Letters, 2001
- Electronic structure and superconducting gap of silicon clathratestudied with ultrahigh-resolution photoemission spectroscopyPhysical Review B, 2001
- Structural properties and thermodynamic stability of Ba-doped silicon type-I clathrates synthesized under high pressurePhysical Review B, 2001
- First-principles study ofclathrates: Direct wide-gap semiconductors in Si-Ge alloysPhysical Review B, 2000
- Low-density framework form of crystalline silicon with a wide optical band gapPhysical Review B, 2000
- Electronic structures of andPhysical Review B, 2000
- NMR study on the stoichiometry of the silicon clathratePhysical Review B, 1999
- Superconductivity in germanium clathratePhysical Review B, 1999
- Superconductivity in the Silicon Clathrate Compound (Na,Ba)SPhysical Review Letters, 1995
- Electronic structure of andPhysical Review B, 1995