  Using density-functional-based methods, we show that the hole-doped
  Li_{x}BC and Na_{x}BC in P6_{3}/mmc crystal structure and C_{x} in graphite
structure are capable of showing superconductivity, possibly with a T_{c} much
higher than that of
  MgB_{2}. We use full-potential methods to obtain the optimized lattice
constants a and c, coherent-potential approximation to describe the effects of
disorder, Gaspari-Gyorffy formalism to obtain the electron-phonon coupling
constant $\lambda$, and Allen-Dynes equation to calculate T_{c} as a function
of hole concentration in these alloys.
