biostudies-literatureCai XMOSTCNew Cornerstone Science FoundationNational Science Foundation of ChinaNational Science Foundation (NSF)e2426111122https://www.ebi.ac.uk/biostudies/studies/S-EPMC12377744biostudies-literatureUnknown122(33)A quantum spin liquid (QSL) is an exotic insulating phase with emergent gauge fields and fractionalized excitations. However, the unambiguous demonstration of the existence of a QSL in a "nonengineered" microscopic model (or in any material) remains challenging. Here, using numerically exact sign-problem-free quantum Monte Carlo simulations, we show that a QSL arises in a nonengineered electron-phonon model. Specifically, we investigate the ground-state phase diagram of the bond Su-Schrieffer-Heeger model on a 2D triangular lattice at (one electron per site), which we show includes a QSL phase which is fully gapped, exhibits no symmetry-breaking order, and supports deconfined fractionalized holon excitations. This suggests promising routes for finding QSLs in realistic materials and high-Tc superconductivity by lightly doping them.Proceedings of the National Academy of Sciences of the United States of AmericaQuantum spin liquid from electron-phonon coupling.PMC12377744Xplorer Prize2021YFA140010012347107DMR-2310312Kivelson SAHan ZYao HCai XLi ZXfalseQuantum spin liquid from electron-phonon coupling.A quantum spin liquid (QSL) is an exotic insulating phase with emergent gauge fields and fractionalized excitations. However, the unambiguous demonstration of the existence of a QSL in a "nonengineered" microscopic model (or in any material) remains challenging. Here, using numerically exact sign-problem-free quantum Monte Carlo simulations, we show that a QSL arises in a nonengineered electron-phonon model. Specifically, we investigate the ground-state phase diagram of the bond Su-Schrieffer-Heeger model on a 2D triangular lattice at (one electron per site), which we show includes a QSL phase which is fully gapped, exhibits no symmetry-breaking order, and supports deconfined fractionalized holon excitations. This suggests promising routes for finding QSLs in realistic materials and high-Tc superconductivity by lightly doping them.2025-01-01T00:00:00Z2025 Aug2026-05-10T04:21:04.618Z2026-04-08T01:28:21.199ZS-EPMC123777444078902810.1073/pnas.2426111122