Toward possibility of high-temperature bipolaronic superconductivity in boron tubular polymorph: Theoretical aspects of transition into anti-adiabatic state Original Research Article

Large diameter single-wall boron nanotubes (SWBNT) produced by 2%Mg–mesoporous Al2O3 catalysis show diamagnetic transition at ∼40 K and ∼80 K, which is a serious indication for possible superconductivity (Iyyamperumal et al., 2009 [10]). Theoretical study which explains or disproves possibility of superconductivity in boron is so far absent, however. Here we apply first-principles formulation of nonadiabatic theory of electron–vibration interactions in study of band structure of boron nanotubes. The ab initio results show that electron–vibration coupling induces in SWBNT with diameter larger than 15 Å transition into anti-adiabatic ground state at distorted-fluxional geometry. Thermodynamic and magnetic properties of anti-adiabatic ground state imply possibility of bipolaronic superconductivity. Calculated critical temperature Tc of large diameter SWBNT is 39 K and inclusion of Mg into a tube increases Tc up to 70–90 K. Presence of Al in SWBNT suppresses superconductivity and a tube remains metallic down to 0 K. Superconducting properties could establish boron nanotubes as a superior material for nanotechnology.