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arXiv 1909.00993cond-mat.str-elquant-ph
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各种温度下扰动对可果美$S=1/2$反铁磁体的影响

Effect of perturbations on the kagome $S=1/2$ antiferromagnet at all temperatures

Bernard Bernu, Laurent Pierre, Karim Essafi, Laura Messio

摘要:

$S=1/2$可果美海森堡反铁磁体的基态现在被认为是一种自旋液体,但它的确切性质仍然没有确定,即使越来越多的线索指向一种无隙自旋液体。我们使用高温系列展开(HTSE)外推的比热$c_V(T)$和磁化率$χ(T)$在整个温度范围内,使用改进的熵方法与自我确定的基态能量每个网站$e_0$。优化算法给出的HTSE系数达到前所未有的数量级(20 in $1/T$),并作为磁场的精确函数。对于$c_V$的不同低$T$行为,给出了三种外推:指数(对于带隙系统)、线性或二次(对于两种不同类型的无隙自旋液体)。我们研究了各种扰动对海森堡哈密顿量的影响:伊辛各向异性,Dzyaloshinskiii-Moriya相互作用,第二和第三邻居相互作用,以及随机分布的磁空位。我们提出了一个实验测定的$χ(T=0)$,这可能是非零的,从$c_V$测量在不同的磁场。

英文摘要:

The ground state of the $S=1/2$ kagome Heisenberg antiferromagnet is now recognized as a spin liquid, but its precise nature remains unsettled, even if more and more clues point towards a gapless spin liquid. We use high temperature series expansions (HTSE) to extrapolate the specific heat $c_V(T)$ and the magnetic susceptibility $χ(T)$ over the full temperature range, using an improved entropy method with a self-determination of the ground state energy per site $e_0$. Optimized algorithms give the HTSE coefficients up to unprecedented orders (20 in $1/T$) and as exact functions of the magnetic field. Three extrapolations are presented for different low-$T$ behaviors of $c_V$: exponential (for a gapped system), linear or quadratic (for two different types of gapless spin liquids). We study the effects of various perturbations to the Heisenberg Hamiltonian: Ising anisotropy, Dzyaloshinskii-Moriya interactions, second and third neighbor interactions, and randomly distributed magnetic vacancies. We propose an experimental determination of $χ(T=0)$, which could be non zero, from $c_V$ measurements under different magnetic fields.

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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