Superconductivity in a background of topological spin texture

¹ Department of Physics and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology - Shenzhen 518055, China
² Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology - Shenzhen 518055, China
³ Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong) Shenzhen 508045, China
⁴ State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University Beijing 100084, China
⁵ Frontier Science Center for Quantum Information - Beijing 100084, China

Received: 5 July 2024
Accepted: 12 November 2024

Abstract

Motivated by a recent experiment on high-temperature superconductors (Wang Z. C. et al., Nature, 615, (2023) 405), we perform a theoretical study to distinguish the nature of the topological spin texture in the superconducting phase of an underdoped cuprate. We propose a phenomenological tight-binding model of electrons with spin-singlet pairing hopping in the background of topological spin texture on the square lattice to capture the coupling of electrons and the topological spin texture. Two types of topological spin texture relevant to the experiment are considered, i.e., Bloch skyrmion and sinusoidal vortex, and the Bogoliubov-de Gennes mean-field theory is employed to calculate the gap functions and local density of states. We discover an emergent d_xy-wave component in the imaginary part of the gap function for skyrmion, but this is not present for vortex. For skyrmion, each coherent peak in the local density of states splits into two spatially uniform peaks, while for vortex, it splits into two spatially modulated peaks. Our study reveals the qualitatively different consequences of two types of topological spin texture, and can be possibly detected in the further STM experiment.