论文标题
Kitaev模型材料中的近端铁磁状态$α$ -rucl $ _ {3} $
Proximate ferromagnetic state in the Kitaev model material $α$-RuCl$_{3}$
论文作者
论文摘要
$α$ -rucl $ _ {3} $是实现Kitaev量子旋转液体的主要候选者，但其锯齿形弹药在低温下的锯齿形抗FiroRomagnetic Order表示与Kitaev模型偏离。我们已经通过ru $ l_ {3} $吸收边缘的谐振X射线散射研究来量化$α$ -rucl $ _ {3} $ $α$ -rucl $ _ {3} $的旋转量。在顺磁性状态下，磁激发的准弹性强度在区域中心周围具有宽阔的最大值，而在锯齿形磁性bragg波vector上没有任何局部最大值。这一发现表明，曲折的顺序是脆弱的，并且通过竞争铁磁相关性易于稳定。实验确定的哈密顿量的经典基态实际上是铁磁。锯齿形状态通过量子“秩序”机制稳定，使铁磁性与基塔耶夫自旋液体一起稳定为能量近端的稳定状态。这三个紧密竞争的状态及其集体激励是对磁场中对$α$ -rucl $ _ {3} $不寻常特性的理论理解的关键。
$α$-RuCl$_{3}$ is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. We have quantified the spin Hamiltonian of $α$-RuCl$_{3}$ by a resonant inelastic x-ray scattering study at the Ru $L_{3}$ absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors. This finding implies that the zigzag order is fragile and readily destabilized by competing ferromagnetic correlations. The classical ground state of the experimentally determined Hamiltonian is actually ferromagnetic. The zigzag state is stabilized via a quantum "order by disorder" mechanism, leaving ferromagnetism -- along with the Kitaev spin liquid -- as energetically proximate metastable states. The three closely competing states and their collective excitations hold the key to the theoretical understanding of the unusual properties of $α$-RuCl$_{3}$ in magnetic fields.
