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

Large diameter single-wall boron nanotubes (SWBNT) produced by 2%Mg-mesoporous Al2O3 catalysis show diamagnetic transition at similar to 40 K and similar to 80 K, which is a serious indication for possible superconductivity (lyyamperumal 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 angstrom 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 T-c of large diameter SWBNT is 39 K and inclusion of Mg into a tube increases T-c 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. (C) 2012 Elsevier Ltd. All rights reserved.