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arXiv · 2603.25245

Spinon Singlet Pairing: Microscopic nature of plaquettes in stripy LDOS

Ying Liang·Yi-Da Chu·Hao Ding·Shi-Jie Hu·Xue-Feng Zhang
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Abstract

Scanning tunneling microscopy (STM) is a powerful tool for visualizing the local density of states (LDOS) of individual stripes in cuprates. However, the microscopic nature of the observed exotic LDOS patterns and their connection to high-$T_c$ superconductivity remain open questions. Within the framework of the quantum colored string model, we reveal that the ubiquitous $4a_0\times4a_0$ plaquettes originate from either the breaking of local spinon singlet pairs through hole insertion, or the formation of an unpaired spinon upon electron addition in a stripe. Moreover, by comparing our data with LDOS of cuprates, we identify an effect of particle-hole symmetry breaking (PHSB): a $2a_0$ shift, which is predicted and confirmed in a longer stripe ($L=18$). At last, we establish and verify a general relation between hole density and plaquette size across multiple fillings. Our work offers a fresh wavefunction-based perspective on interpreting STM signals in cuprate experiments and demonstrates that their origin may arise from spinon singlet pairing in the ground state of fluctuating stripes, the same mechanism underlying the $d$-wave sign structure [Phys. Rev. Lett. \textbf{137}, 086702 (2026)].

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Ying Liang, Yi-Da Chu, Hao Ding, Shi-Jie Hu, Xue-Feng Zhang. 2026-03-26. Spinon Singlet Pairing: Microscopic nature of plaquettes in stripy LDOS. https://arxiv.org/abs/2603.25245

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