Excitonic quasiparticles in a spin-orbit Mott insulator
Excitonic quasiparticles in a spin-orbit Mott insulator
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DOI：
10.1038/ncomms5453
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发表时间：
2014-07-01
影响因子：
16.6
通讯作者：
Kim, B. J.
中科院分区：
文献类型：
--
作者：
Kim, Jungho;Daghofer, M.;Kim, B. J.
在凝聚态物质系统中，在大量相互作用的自由度中出现了弱耦合准粒子（QP），大多数物理性质都是用它来描述的。缺乏对此类 QP 的识别是理解相关电子的无数奇异特性（例如非常规超导性和非费米液体行为）的主要障碍。在这里，我们报告了在准二维自旋 - 1/2 反铁磁体 Sr2IrO4 - 一种由磁振子包裹的激子 - 中观察到的复合粒子，其以 QP 的典型特征传播：有限的 QP 残数和比跳跃时间尺度更长的寿命。这种电荷中性激发的动力学反映了自旋 1/2 背景下类似单空穴传播的基本过程，并揭示了掺杂到二维铜酸盐中的单个带电空穴所掩盖的相同的内在动力学。
In condensed matter systems, out of a large number of interacting degrees of freedom emerge weakly coupled quasiparticles (QPs), in terms of which most physical properties are described. The lack of identification of such QPs is a major barrier for understanding myriad exotic properties of correlated electrons, such as unconventional superconductivity and non-Fermi liquid behaviours. Here we report the observation of a composite particle in a quasi-two-dimensional spin-1/2 antiferromagnet Sr2IrO4-an exciton dressed with magnons-that propagates with the canonical characteristics of a QP: a finite QP residue and a lifetime longer than the hopping time scale. The dynamics of this charge-neutral excitation mirrors the fundamental process of the analogous one-hole propagation in the background of spins-1/2, and reveals the same intrinsic dynamics that is obscured for a single, charged-hole doped into two-dimensional cuprates.