论文标题
在规范轨道系统中拆开轨道物理kcuf $ _3 $
Unraveling the orbital physics in a canonical orbital system KCuF$_3$
论文作者
论文摘要
我们探讨了典型的轨道系统KCUF $ _3 $中集体轨道激发，轨道的存在。使用Cu $ L_3 $ - 边缘谐振非弹性X射线散射我们表明，非分散性高能量峰是由Cu $^{2+} $ $ dd $ orbital激发产生的。这些高能量模式与基于单个群集的{\ it ab-initio}量子化学计算表明，表明$ dd $激发是高度局部化的。同时，低能激发呈现出明显的分散。在与Mueller Ansatz计算进行比较之后，它们与两翼连续体非常好。局部$ DD $激发和强烈分散磁激发的观察表明，轨道分散剂低于分辨率检测极限。我们的结果可以与kcuf $ _3 $中强的{\ it local} jahn-teller效应进行调和，这主要是驱动轨道订购的。
We explore the existence of the collective orbital excitations, orbitons, in the canonical orbital system KCuF$_3$. Using the Cu $L_3$-edge resonant inelastic X-ray scattering we show that the non-dispersive high-energy peaks result from the Cu$^{2+}$ $dd$ orbital excitations. These high-energy modes show good agreement with the {\it ab-initio} quantum chemistry calculation based on a single cluster, indicating that the $dd$ excitations are highly localized. At the same time, the low-energy excitations present clear dispersion. They match extremely well with the two-spinon continuum following the comparison with Mueller Ansatz calculations. The localized $dd$ excitations and the observation of the strongly dispersive magnetic excitations suggest that orbiton dispersion is below the resolution detection limit. Our results can reconcile with the strong {\it local} Jahn-Teller effect in KCuF$_3$, which predominantly drives orbital ordering.
