Carbon Doping in MgB_2 : Role of Boron and Carbon p_x(y) Bands
arXiv:cond-mat/0304436 · doi:10.1016/S0038-1098(03)00426-5
Abstract
We have studied the changes in the electronic structure and the superconducting transition temperature T_c of Mg(B_{1-x}C_{x})_{2} alloys as a function of x with 0\leq x\leq 0.3. Our density-functional-based approach uses coherent-potential approximation to describe the effects of disorder, Gaspari-Gyorffy formalism to estimate the electron-phonon matrix elements and Allen-Dynes equation to calculate T_c in these alloys. We find that the changes in the electronic structure of Mg(B_{1-x}C_{x})_{2} alloys, especially near the Fermi energy E_F, come mainly from the outward movement of E_F with increasing x, and the effects of disorder in the B plane are small. In particular, our results show a sharp decline in both B and C p_{x(y)} states for 0.2\leq x\leq 0.3. Our calculated variation in T_{c} of Mg(B_{1-x}C_{x})_{2} alloys is in qualitative agreement with the experiments.
arXiv comment9 pages, 5 figures
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Cited by in corpus (6)
- Evidence for Single-gap Superconductivity in Mg(B_{1-x}C_x)_2 Single Crystals with x=0.132 from Point-Contact Spectroscopy
- Enhancement of the irreversibility field by carbon substitution in single crystal MgB
- On Heavy Carbon Doping of MgB
- Electron-phonon coupling and two-band superconductivity of Al- and C-doped MgB2
- Raman Scattering Investigation of Electron Phonon Coupling in Carbon substituted MgB2
- Is Delta_{pi}-gap-only superconductivity possible in Mg_{1-x}Al_{x}B_{2} and Mg(B_{1-y}C_{y})_{2} alloys?