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arXiv 0906.0960cond-mat.str-el
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体心立方晶格上S = 1/2受抑海森堡反铁磁体的非线性自旋波理论结果

Non-linear spin wave theory results for the frustrated S = 1/2 Heisenberg antiferromagnet on a body-centered cubic lattice

Kingshuk Majumdar, Trinanjan Datta

摘要:

利用非线性自旋波理论研究了零温下具有竞争第一和第二近邻交换(J1和J2)的体心立方晶格上量子自旋1/2海森堡反铁磁体的亚晶格磁化强度.该模型的零温相由小J_2(AF_1)的两个亚晶格Néel相和大J_2(AF_2)的共线相组成。我们发现,由于自旋波相互作用的四次修正增强了AF_1和AF_2相的亚晶格磁化强度。在模型的经典转变点附近和J_2> J_1区域,磁化强度修正是显著的。计算了四次相互作用下的基态能量。结果表明,在四次修正下,AF_1和AF_2相之间的一级相变(以前在本模型中观察到的)仍然存在。

英文摘要:

At zero temperature the sublattice magnetization of the quantum spin-1/2 Heisenberg antiferromagnet on a body-centered cubic lattice with competing first and second neighbor exchange (J1 and J2) is investigated using the non-linear spin wave theory. The zero temperature phases of the model consist of a two sublattice Néel phase for small J_2 (AF_1) and a collinear phase at large J_2 (AF_2). We show that quartic corrections due to spin-wave interactions enhance the sublattice magnetization in both the AF_1 and the AF_2 phase. The magnetization corrections are prominent near the classical transition point of the model and in the J_2> J_1 regime. The ground state energy with quartic interactions is also calculated. It is found that up to quartic corrections the first order phase transition (previously observed in this model) between the AF_1 and the AF_2 phase survives.

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