DMRG Numerical Study of the Kagom\'e Antiferromagnet
Abstract
We numerically study the spin-1/2 antiferromagnetic Heisenberg model on the kagom\'e lattice using the density-matrix renormalization group (DMRG) method. We find that the ground state is a magnetically disordered spin liquid, characterized by an exponential decay of spin-spin correlation function in real space and a magnetic structure factor showing system-size independent peaks at commersurate antiferromangetic wavevectors. We obtain a spin triplet excitation gap E(S=1)=0.055 0.005 by extrapolation based on the large size results, and confirm the presence of gapless singlet excitations. The physical nature of such an exotic spin liquid is also discussed.
0