Spectra of a Gapped Quantum Spin Liquid with a Strong Chiral Excitation on the Triangular Lattice*

While a quantum spin liquid (QSL) phase has been identified in the J1-J2 Heisenberg model on a triangular lattice via numerical calculations, debate persists about whether or not such a QSL is gapped or gapless, with contradictory conclusions from different techniques. Moreover, information about excitations and dynamics is crucial for the experimental detection of such a phase. In this work, we use exact diagonalization to characterize signatures of a QSL phase on the triangular lattice through the dynamical spin structure factor S(q, ω) and Raman susceptibility χ(ω). We find that spectra for the QSL phase show distinct features compared to those of neighboring phases; and both the Raman spectra and spin structure factor show gapped behaviour in the QSL phase. Interestingly, there is a prominent excitation mode in the Raman A2 channel, indicating a strong subleading tendency toward a chiral spin liquid phase.