We study the spin liquid candidate of the spin-1/2J1-J2 Heisenberg antiferromagnet on the triangular lattice by means of density matrix renormalization group (DMRG) simulations. By applying an external Aharonov-Bohm flux insertion in an infinitely long cylinder, we find unambiguous evidence for gapless U(1) Dirac spin liquid behavior. The flux insertion overcomes the finite size restriction for energy gaps and clearly shows gapless behavior at the expected wave-vectors. Using the DMRG transfer matrix, the low-lying excitation spectrum can be extracted, which shows characteristic Dirac cone structures of both spinon-bilinear and monopole excitations. Finally, we confirm that the entanglement entropy follows the predicted universal response under the flux insertion.
@article{arxiv.1905.09837,
title = {Dirac Spin Liquid on the Spin-1/2 Triangular Heisenberg Antiferromagnet},
author = {Shijie Hu and W. Zhu and Sebastian Eggert and Yin-Chen He},
journal= {arXiv preprint arXiv:1905.09837},
year = {2019}
}