Superconductivity from doping boron icosahedra

We propose an alternative route to achieve the superconducting state in boron-rich solids, the hole doping of B12 icosahedra. For this purpose we consider a prototype metallic phase of B13C2. We show that in this compound the boron icosahedral units are mainly responsible for the large phonon frequencies logarithmic average, 65.8 meV, and the moderate electron-phonon coupling λ=0.81. We suggest that this high Tc could be a general feature of hole-doped boron icosahedral solids. Moreover our calculated moderate value of λ excludes the formation of bipolarons localized on the icosahedral length scale as suggested by previous authors.