  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 "non-engineered" 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 non-engineered
electron-phonon model. Specifically, we investigate the ground-state phase
diagram of the bond Su-Schrieffer-Heeger (SSH) model on a 2D triangular lattice
at half filling (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 new routes for
finding QSLs in realistic materials and high-$T_c$ superconductivity by lightly
doping them.
