On Heavy Carbon Doping of MgB$_2$
| dc.creator | Kasinathan, Deepa | |
| dc.creator | Lee, K. -W. | |
| dc.creator | Pickett, W. E. | |
| dc.date | 2004-09-22 | |
| dc.date.accessioned | 2026-07-25T23:18:05Z | |
| dc.description | Heavy carbon doping of MgB$_2$ is studied by first principles electronic structure studies of two types, an ordered supercell (Mg(B$_{1-x}$C$_{x}$)$_{2}$,x=0.0833) and also the coherent potential approximation method that incorporates effects of B-C disorder. For the ordered model, the twofold degenerate $σ$-bands that are the basis of the high temperature superconductivity are split by 60 meV (i.e.7 meV/%C) and the $σ$ Fermi cylinders contain 0.070 holes/cell, compared to 0.11 for MgB$_2$. A virtual crystal treatment tends to overestimate the rate at which $σ$ holes are filled by substitutional carbon. The coherent potential approximation (CPA) calculations give the same rate of band filling as the supercell method. The occupied local density of states of C is almost identical to that of B in the upper 2 eV of the valence bands, but in the range -8 eV to -2 eV, C has a considerably larger density of states. The calculations indicate that the $σ$ Fermi surface cylinders pinch off at the zone center only above the maximum C concentration x ~ 0.10. These results indicate that Mg(B$_{1-x}$C$_{x}$)$_{2}$ as well as Mg$_{1-x}$Al$_x$B$_2$ is a good system in which to study the evolution of the unusual electron-phonon coupling character and strength as the crucial $σ$ hole states are filled. | |
| dc.description | 8 pages, 8 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0409563 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0409563 | |
| dc.identifier | Physica C 424, 116 (2005) | |
| dc.identifier | doi:10.1016/j.physc.2005.05.002 | |
| dc.identifier.uri | https://dspace.dare.co.zw/handle/123456789/97225 | |
| dc.subject | Superconductivity | |
| dc.subject | Materials Science | |
| dc.title | On Heavy Carbon Doping of MgB$_2$ | |
| dc.type | text |