Feshbach shape resonance for high Tc superconductivity in superlattices of nanotubes

TL;DR

This paper explores how Feshbach shape resonances in doped nanotube superlattices can enhance high-temperature superconductivity by tuning the electronic structure at a Lifshitz transition, leading to multiband effects.

Contribution

It introduces a mechanism where Feshbach shape resonances in nanotube superlattices boost Tc by exploiting Lifshitz electronic topological transitions.

Findings

Feshbach resonances can significantly increase Tc in nanotube superlattices.

Multiband superconductivity is facilitated by asymmetric gaps and spatially separated wave functions.

Tuning the chemical potential at the Lifshitz transition optimizes superconducting properties.

Abstract

The case of a Feshbach shape resonance in the pairing mechanism for high T c superconductivity in a crystalline lattice of doped metallic nanotubes is described. The superlattice of doped metallic nanotubes provides a superconductor with a strongly asymmetric gap. The disparity and different spatial locations of the wave functions of electrons in different subbands at the Fermi level should suppress the single electron impurity interband scattering giving multiband superconductivity in the clean limit. The Feshbach resonances will arise from the component single-particle wave functions out of which the electron pair wave function is constructed: pairs of wave functions which are time inverse of each other. The Feshbach shape resonance increases the critical temperature by tuning the chemical potential at the Lifshitz electronic topological transition (ETT) where the Fermi surface of one of the bands changes from the one dimensional (1D) to the two dimensional (2D) topology (1D/2D ETT).