title: Valence-bond spin-liquid state in two-dimensional frustrated spin-1/2 Heisenberg antiferromagnets.
abstract: Fermionic valence-bond approach in terms of SU(4) representation is proposed to describe the J1-J2 frustrated Heisenberg antiferromagnetic (AF) model on a bipartite square lattice. A uniform mean field solution without breaking the translational and rotational symmetries describes a valence-bond spin-liquid state, interpolating the two different AF ordered states in the large J1 and large J2 limits, respectively. This novel spin-liquid state is gapless with the vanishing density of states at the Fermi nodal points. Moreover, a sharp resonance peak in the dynamic structure factor is predicted for momenta q=(0,0) and (pi,pi) in the strongly frustrated limit J(2)/J(1) approximately 1/2, which can be checked by neutron scattering experiments.
authors.affiliation: Center for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Hu
authors.forename: Lu
authors.initials: L
authors.lastname: Yu