ISSN:
1432-2234
Keywords:
Rhombohedral boron compounds
;
Band structure
;
Density of states
;
Cluster model
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The electronic band structures of the rhombohedral-based boron compounds α-B12, B12P2 and B12 As2 have been investigated along all symmetry directions. The calculations show that the band gap, in all cases, is of the order of 2 eV, which correlates with the known color of α-rhombohedral boron. The materials should be intrinsic semi-conductors, as has recently been shown experimentally. The states around the band gap in α-B12 are dominated by the boron 2p atomic states. The bonding in the icosahedra, as illuminated by cluster calculations, is shown to be rather similar to that in the isolated B12 icosahedron. Of the intericosahedron interactions, those between B(2) and B(2) atoms are the strongest and have a bond index just above unity. In B12P2 the orbitals of the P2 moiety make a significant contribution to the valence band edge states and the conduction band edge states also incorporate considerable (55%) phosphorus 3d orbital character. In B12As2 the arsenic 4d orbitals do not have as much effect in that crystal as do the 3d orbitals in B12P2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00554234
Permalink
