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

TL;DR

This paper uses first-principles calculations to explore the potential for high-temperature bipolaronic superconductivity in boron nanotubes, showing that doping and structural factors significantly influence their superconducting properties.

Contribution

It provides a theoretical analysis of electron-vibration interactions in boron nanotubes, predicting conditions for bipolaronic superconductivity and estimating critical temperatures.

Findings

Large diameter SWBNT can transition into an anti-adiabatic state.

Doping with Mg raises Tc up to 70-90 K.

Presence of Al suppresses superconductivity.

Abstract

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 (J.Phys.Chem.C113, (2009) 17661). 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 {\AA} 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 suppress superconductivity and a tube remains metallic down to 0 K. Superconducting properties could established boron nanotubes superior material for nanotechnology.