Characterizing the Spin-½ Heisenberg model on the triangular lattice through the Dynamical Spin Structure

The ground state phase of the spin-1/2 Heisenberg model on the triangular lattice with nearest-neighbor exchange J₁ can be frustrated by the next nearest neighbor coupling J₂ and turns into a stripe phase for large J₂. While both small and large values of J₂/J₁ lead to magnetically ordered phases, a spin liquid phase with short correlation length can be established at intermediate values. However, the nature of this spin liquid phase remains under debate, with finite size DMRG calculations suggesting a gapped Z₂ spin liquid phase, but also showing possible gapless spinon excitations. Here, we use exact diagonalization on a series of finite-size clusters to analyze the character of the ground state and lowest-lying the excited states of the model for various values of J₂. We further characterize the evolution of the model as a function of J₂ by analyzing the dynamical spin structure factor S(q,w) to provide key information on the changes of the underlying magnetic structure.