Weak-coupling calculation of the gap structure of doped n-leg Hubbard ladders

TL;DR

This paper investigates the gap structure in doped n-leg Hubbard ladders using a weak-coupling approach, focusing on spin gaps and pair removal amplitudes to understand pairing mechanisms.

Contribution

It introduces a spin-fluctuation exchange approximation to analyze the gap structure and pair internal structure in doped Hubbard ladders, providing new insights into pairing phenomena.

Findings

Spin gap reflects energy to break pairs into quasiparticles.

Calculated pair removal amplitude reveals internal pair structure.

Results enhance understanding of pairing in doped Hubbard ladders.

Abstract

In weak coupling, the spin gap in doped, even, n-leg periodic Hubbard ladders reflects the energy to break a pair into separate quasiparticles. Here we investigate the structure of the gap within a spin-fluctuation exchange approximation. We also calculate the amplitude for removing a singlet pair from two lattice sites separated by a distance (l_x,l_y), which describes the internal structure of a pair.