Spin-orbital separation in the quasi-one-dimensional Mott insulator Sr2CuO3
Spin-orbital separation in the quasi-one-dimensional Mott insulator Sr2CuO3
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DOI：
10.1038/nature10974
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发表时间：
2012-05-03
期刊：
影响因子：
64.8
通讯作者：
Schmitt, T.
中科院分区：
文献类型：
--
作者：
Schlappa, J.;Wohlfeld, K.;Schmitt, T.
当被看作基本粒子时，电子既有自旋又有电荷。当与原子核结合时，它也获得了对应于它所占据的量子化原子轨道的角动量量子数。即使固体中的电子形成能带并从原子核离域，在莫特绝缘体中，它们仍然保持其三个基本量子数：自旋，电荷和轨道（1）。一维物理学的标志是基本电子分裂成独立的自由度（2）。电子分离成独立的准粒子，它们携带自旋（自旋子）或电荷（holon），这一现象在15年前首次被观察到（3）。在这里，我们报告的观察分离的轨道自由度（orbiton）使用共振非弹性X射线散射的一维莫特绝缘体Sr2CuO3。我们解决了一个轨道分离自己的自旋和传播通过晶格作为一个独特的准粒子与大量的分散在能量超过动量，约0.2电子伏特，在近一个布里渊区。
When viewed as an elementary particle, the electron has spin and charge. When binding to the atomic nucleus, it also acquires an angular momentum quantum number corresponding to the quantized atomic orbital it occupies. Even if electrons in solids form bands and delocalize from the nuclei, in Mott insulators they retain their three fundamental quantum numbers: spin, charge and orbital(1). The hallmark of one-dimensional physics is a breaking up of the elementary electron into its separate degrees of freedom(2). The separation of the electron into independent quasi-particles that carry either spin (spinons) or charge (holons) was first observed fifteen years ago(3). Here we report observation of the separation of the orbital degree of freedom (orbiton) using resonant inelastic X-ray scattering on the one-dimensional Mott insulator Sr2CuO3. We resolve an orbiton separating itself from spinons and propagating through the lattice as a distinct quasi-particle with a substantial dispersion in energy over momentum, of about 0.2 electronvolts, over nearly one Brillouin zone.