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arXiv 0909.3723cond-mat.str-elcond-mat.stat-mech
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正方晶格上自旋为1/2的J1-J2海森堡反铁磁体:N=40自旋的精确对角化

The spin-1/2 J1-J2 Heisenberg antiferromagnet on the square lattice: Exact diagonalization for N=40 spins

J. Richter, J. Schulenburg

摘要:

本文给出了N=40格点的有限正方晶格上自旋为1/2的J1-J2海森堡反铁磁体的基态和低激发的精确数值计算结果。使用有限尺寸外推法,我们确定的基态能量,磁序参量,自旋间隙,均匀磁化率,以及自旋波速度和自旋刚度作为阻挫参数J2/J1的函数。与通常的例外情况一致,我们发现J2 < J2^{c1}和J2 > J2^{c2}的半经典磁有序相被带隙的量子顺磁相分开。我们估计J2^{c1} \approx 0.35 J1和J2^{c2} \approx 0.66 J1。

英文摘要:

We present numerical exact results for the ground state and the low-lying excitations for the spin-1/2 J1-J2 Heisenberg antiferromagnet on finite square lattices of up to N=40 sites. Using finite-size extrapolation we determine the ground-state energy, the magnetic order parameters, the spin gap, the uniform susceptibility, as well as the spin-wave velocity and the spin stiffness as functions of the frustration parameter J2/J1. In agreement with the generally excepted scenario we find semiclassical magnetically ordered phases for J2 < J2^{c1} and J2 > J2^{c2} separated by a gapful quantum paramagnetic phase. We estimate J2^{c1} \approx 0.35J1 and J2^{c2} \approx 0.66J1.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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