Superconductivity from doping boron icosahedra

Abstract

We propose an alternative route to achieve the superconducting state in boron-rich solids, the hole doping of ${\mathrm{B}}_{12}$ icosahedra. For this purpose we consider a prototype metallic phase of ${\mathrm{B}}_{13}{\mathrm{C}}_{2}$. We show that in this compound the boron icosahedral units are mainly responsible for the large phonon frequencies logarithmic average, $65.8\phantom{\rule{0.3em}{0ex}}\text{meV}$, and the moderate electron-phonon coupling $\ensuremath{\lambda}=0.81$. We suggest that this high ${T}_{c}$ could be a general feature of hole-doped boron icosahedral solids. Moreover our calculated moderate value of $\ensuremath{\lambda}$ excludes the formation of bipolarons localized on the icosahedral length scale as suggested by previous authors.