Dichotomy in underdoped high $T_c$ superconductors and spinon-dopon approach to $t$-$t'$-$t''$-$J$ model

TL;DR

This paper introduces a spinon-dopon approach to the $t$-$t'$-$t''$-$J$ model to explain the spectral dichotomy in underdoped high-$T_c$ superconductors, linking non-uniform mixing to observed electron spectral weight variations.

Contribution

It proposes a novel spinon-dopon framework with a Monte Carlo method to explain spectral weight dichotomy, aligning theoretical results with experimental data.

Findings

Non-uniform mixing lowers $t'$ and $t''$ hopping energy.

Spectral weight $Z_-$ correlates with spinon-dopon mixing.

Results match experimental electron spectral weight patterns.

Abstract

We studied underdoped high $T_c$ superconductors using a spinon-dopon approach (or doped-carrier approach) to $t$-$t'$-$t''$-$J$ model, where spinon carries spin and dopon carries both spin and charge. In this approach, the mixing of spinon and dopon describes superconductivity. We found that a nonuniform mixing in $k$-space is most effective in lowering the $t'$ and $t''$ hopping energy. We showed that at mean-field level, the mixing is proportional to quasiparticle spectral weight $Z_-$. We also found a simple monte-carlo algorithm to calculate $Z_{-}$ from the projected spinon-dopon wavefunction, which confirms the mean-field result. Thus the non-uniform mixing caused by $t'$ and $t"$ explains the different electron spectral weights near the nodal and anti-nodal points ({\it i.e.} the dichotomy) observed in underdoped high $T_c$ superconductors. For hole-doped sample, we found that $Z$ is enhanced in the nodal region and suppressed in the anti-nodal region. For electron doped sample, the same approach leads to a suppressed $Z$ in the nodal region and enhanced in the anti-nodal region, in agreement with experimental observations.