Spinon confinement and a sharp longitudinal mode in Yb2Pt2Pb in magnetic fields
Spinon confinement and a sharp longitudinal mode in Yb2Pt2Pb in magnetic fields
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DOI：
10.1038/s41467-019-08715-y
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发表时间：
2019-03-08
影响因子：
16.6
通讯作者：
Aronson, M. C.
中科院分区：
文献类型：
--
作者：
Gannon, W. J.;Zaliznyak, I. A.;Aronson, M. C.
自旋为1/2的反铁磁链中的基本激发是自旋子，即当成对结合时形成三重激发连续体的非受限分数准粒子。在类似伊辛的自旋链中，连续统是带隙的，基态是尼尔有序的。在这里，我们报告了高分辨率的中子散射实验，它揭示了磁场如何闭合这个间隙并将Yb 2 Pt 2 Pb中的自旋链驱动到临界的、无序的Luttinger液态。在Yb 2 Pt 2 Pb的有效自旋-1/2描述的大，伊辛样Yb磁矩的动态，确保所测量的激发是完全纵向的，我们发现，这是很好地描述了时间依赖的密度矩阵重整化群计算。链间耦合导致自旋子的禁闭，自旋子是量子色动力学中夸克禁闭的凝聚态类似物。不敏感的横向波动，我们的测量显示如何产生一个无间隙的，色散的纵向模式从限制和磁顺序的演变。
The fundamental excitations in an antiferromagnetic chain of spins-1/2 are spinons, de-confined fractional quasiparticles that when combined in pairs, form a triplet excitation continuum. In an Ising-like spin chain the continuum is gapped and the ground state is Neel ordered. Here, we report high resolution neutron scattering experiments, which reveal how a magnetic field closes this gap and drives the spin chains in Yb2Pt2Pb to a critical, disordered Luttinger-liquid state. In Yb2Pt2Pb the effective spins-1/2 describe the dynamics of large, Ising-like Yb magnetic moments, ensuring that the measured excitations are exclusively longitudinal, which we find to be well described by time-dependent density matrix renormalization group calculations. The inter-chain coupling leads to the confinement of spinons, a condensed matter analog of quark confinement in quantum chromodynamics. Insensitive to transverse fluctuations, our measurements show how a gapless, dispersive longitudinal mode arises from confinement and evolves with magnetic order.