Zhang Guang-Ming, Hu Hui, Yu Lu
Center for Advanced Study, Tsinghua University, Beijing 100084, China.
Phys Rev Lett. 2003 Aug 8;91(6):067201. doi: 10.1103/PhysRevLett.91.067201. Epub 2003 Aug 7.
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.
提出了基于SU(4)表示的费米子价键方法来描述二分正方晶格上的J1-J2受挫海森堡反铁磁（AF）模型。一种不破坏平移和旋转对称性的均匀平均场解描述了一种价键自旋液体状态，分别在大J1和大J2极限下插值两种不同的AF有序状态。这种新颖的自旋液体状态是无隙的，在费米节点处态密度消失。此外，在强受挫极限J(2)/J(1)≈1/2时，预测动态结构因子在动量q=(0,0)和(π,π)处有一个尖锐的共振峰，这可以通过中子散射实验来检验。
