Qualitative picture of a new mechanism for high-Tc superconductors

TL;DR

This paper proposes a new qualitative mechanism for high-Tc superconductivity that integrates features of stripe phases, preformed pairs, and spin-bags to explain various experimental observations in underdoped cuprates.

Contribution

It introduces a novel mechanism combining stripe, preformed pairs, and spin-bag concepts to qualitatively explain high-Tc phenomena and experimental data.

Findings

Explains enhanced Nernst effect and diamagnetism above Tc

Accounts for pseudogap and pairing gap continuity

Describes stabilization of pre-formed pairs via Coulomb repulsion

Abstract

Xu et al. observed enhanced Nernst effect and Iguchi et al. observed patched diamagnetism, both well above $T_c$ in underdoped high-$T_c$ superconductors (HTSCs). A new mechanism is proposed here, which seems to naturally explain, at least qualitatively, these observations, as well as the d-wave nature and continuity of pseudogap and pairing gap, the tunneling conductance above $T_c$, as well as $T^*(x)$, $T_{\nu}(x)$, $T_c(x)$, etc. This mechanism combines features of dynamic charged stripes, preformed pairs, and spin-bags: At appropriete doping levels, the doped holes (and perhaps also electrons) will promote the formation of anti-phase islands in short-range anti-ferromagnetic order. On the boundary of each such island reside two doped carriers; the unscreened Coulomb repulsion between them stabilizes its size. Superconductivity results when such ``pre-formed pairs'' Bose-condense.