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arXiv 0806.3825cond-mat.str-el
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正方晶格上自旋为1/2的J_1-J_2海森堡反铁磁体的基态相:高阶耦合团簇处理

Ground-state phases of the spin-1/2 J_1-J_2 Heisenberg antiferromagnet on the square lattice: A high-order coupled cluster treatment

R. Darradi, O. Derzhko, R. Zinke, J. Schulenburg, S. E. Krueger, J. Richter

摘要:

利用高阶近似的耦合集团方法和互补精确对角化方法研究了正方晶格上自旋为1/2的$J_1$ -- $J_2$阻挫海森堡反铁磁体的基态性质.我们计算了基态能量、磁序参量、自旋刚度和几种广义磁化率,以探测磁无序量子价键相。我们发现Néel阶和共线阶的量子临界点分别是$J_2^{c1}\approx (0.44 \pm 0.01)J_1$和$J_2^{c2}\approx (0.59 \pm 0.01)J_1$,这与用其它近似方法得到的结果是一致的.与[Sirker et al. Phys. Rev. B { \bf 73},184420(2006)]最近的研究相反,我们的数据没有提供从Néel到价键固态的转变是一级的证据。此外,我们的结果是有利于解除限制的情况下,相变。我们还讨论了磁无序量子相位的性质。

英文摘要:

Using the coupled cluster method for high orders of approximation and complementary exact diagonalization studies we investigate the ground state properties of the spin-1/2 $J_1$--$J_2$ frustrated Heisenberg antiferromagnet on the square lattice. We have calculated the ground-state energy, the magnetic order parameter, the spin stiffness, and several generalized susceptibilities to probe magnetically disordered quantum valence-bond phases. We have found that the quantum critical points for both the Néel and collinear orders are $J_2^{c1}\approx (0.44 \pm 0.01)J_1$ and $J_2^{c2}\approx (0.59 \pm 0.01)J_1$ respectively, which are in good agreement with the results obtained by other approximations. In contrast to the recent study by [Sirker et al. Phys. Rev. B {\bf 73}, 184420 (2006)], our data do not provide evidence for the transition from the Néel to the valence-bond solid state to be first order. Moreover, our results are in favor of the deconfinement scenario for that phase transition. We also discuss the nature of the magnetically disordered quantum phase.

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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