arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1507.04738cond-mat.str-el
收藏

Kagome晶格上几乎经典反铁磁体的强量子效应

Strong quantum effects in an almost classical antiferromagnet on a kagome lattice

A. L. Chernyshev

摘要:

阻挫自旋系统有两个普遍存在的特徴:基态的大量简并性和平坦或无色散的激发分支。在实际材料中,前者经常被次级相互作用或量子涨落提升,有利于有序或自旋液体状态,但后者通常会存活下来。我们证明,平坦模式可能沉淀非常强的量子效应,即使在系统中,否则注销几乎完全经典。由此产生的光谱特征应该让人想起量子系统中的准粒子击穿,只是在这里,自旋激发分支的平坦性强烈地放大了这种效应,导致即使在$S\!\gg\!1$下也不会消失的阻尼。我们提供了一个理论分析的$S=5/2$铁黄钾铁矾的激发光谱,以说明我们的研究结果,并建议进一步研究这个和其他挫折自旋系统。

英文摘要:

Two ubiquitous features of frustrated spin systems stand out: massive degeneracy of their ground states and flat, or dispersionless, excitation branches. In real materials, the former is frequently lifted by secondary interactions or quantum fluctuations, in favor of an ordered or spin-liquid state, but the latter often survive. We demonstrate that flat modes may precipitate remarkably strong quantum effects even in the systems that are otherwise written off as almost entirely classical. The resultant spectral features should be reminiscent of the quasiparticle breakdown in quantum systems, only here the effect is strongly amplified by the flatness of spin-excitation branches, leading to the damping that is not vanishingly small even at $S\!\gg\!1$. We provide a theoretical analysis of excitation spectrum of the $S=5/2$ iron-jarosite to illustrate our findings and to suggest further studies of this and other frustrated spin systems.

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。

↑