2016/11/18 by Yin-Chen He, Michael P. Zaletel, Masaki Oshikawa +1 · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevx.7.031020
published as Phys. Rev. X 7, 031020 (2017) · 15 pages, 16 figures
arxiv created 2016/11/18 · arxiv updated 2017/08/02
The antiferromagnetic spin-1/2 Heisenberg model on a kagome lattice is one of the most paradigmatic models in the context of spin liquids, yet the precise nature of its ground state is not understood. We use large scale density matrix normalization group simulations (DMRG) on infinitely long cylinders and find indications for the formation of a gapless Dirac spin liquid. First, we use adiabatic flux insertion to demonstrate that the spin gap is much smaller than estimated from previous DMRG simulation. Second, we find that the momentum dependent excitation spectrum, as extracted from the DMRG transfer matrix, exhibits Dirac cones that match those of a π-flux free fermion model (the parton mean-field ansatz of a U(1) Dirac spin liquid)