Half-Skyrmion theory for high-temperature superconductivity

TL;DR

This paper reviews the half-Skyrmion theory for high-temperature superconductivity in cuprates, explaining how doped holes create topological spin textures that lead to superconductivity and pseudogap phenomena.

Contribution

It introduces the concept of half-Skyrmions as key excitations in cuprates, linking topological spin textures to superconductivity and pseudogap behavior, supported by numerical simulations and spectral comparisons.

Findings

Half-Skyrmions carry non-zero topological charge below 30% doping.

Incommensurate peaks in magnetic structure factor due to stripe configurations.

Half-Skyrmion interactions induce d_{x^2-y^2}-wave superconductivity.

Abstract

We review the half-Skyrmion theory for copper-oxide high-temperature superconductivity. In the theory, doped holes create a half-Skyrmion spin texture which is characterized by a topological charge. The formation of the half-Skyrmion is described in the single hole doped system, and then the half-Skyrmion excitation spectrum is compared with the angle-resolved photoemission spectroscopy results in the undoped system. Multi-half-Skyrmion configurations are studied by numerical simulations. We show that half-Skyrmions carry non-vanishing topological charge density below a critical hole doping concentration \sim 30% even in the absence of antiferromagnetic long-range order. The magnetic structure factor exhibits incommensurate peaks in stripe ordered configurations of half-Skyrmions and anti-half-Skyrmions. The interaction mediated by half-Skyrmions leads to d_{x^2-y^2}-wave superconductivity. We also describe pseudogap behavior arising from the excitation spectrum of a composite particle of a half-Skyrmion and doped hole.