Magnetic excitations and amplitude fluctuations in insulating cuprates
Magnetic excitations and amplitude fluctuations in insulating cuprates
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DOI：
10.1103/physrevb.97.024407
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发表时间：
2017-05
影响因子：
3.7
通讯作者：
N. Chelwani;A. Baum;T. Bohm;M. Opel;F. Venturini;L. Tassini;A. Erb;H. Berger;L. Forr'o
中科院分区：
文献类型：
--
作者：
N. Chelwani;A. Baum;T. Bohm;M. Opel;F. Venturini;L. Tassini;A. Erb;H. Berger;L. Forr'o
本文介绍了三种绝缘反铁磁铜氧化物YBa 2Cu 3 O、BiSr 2 YCu 2 O和LaCu 4的光散射实验结果，它们是极化和激发能的函数。从原始数据中，我们推导出了光谱分辨光谱。发现$B {1g}$对称性的谱形几乎是普适的，与激发能无关。光谱与场论[\onlinecite{Weidinger：2015}]的预测定量一致，有助于精确提取海森堡耦合$J$。{In此外，发现高能侧的非对称线形与磁化强度的振幅起伏有关。在单独的La 2CuO 4中，可以识别出来自共振效应的微小贡献。其他对称中的谱并不普适。这些变化可以追溯到弱共振效应和外部贡献。对于所有三种化合物，我们发现支持的手征激发的存在出现作为一个连续的$A_{2g}$对称性的起始略低于$3J$。在La 2CuO 4中，在A 2g连续谱的顶部出现了一个孤立的激发。
We present results from light scattering experiments on three insulating antiferromagnetic cuprates, YBa$_2$Cu$_3$O$_{6.05}$, Bi$_2$Sr$_2$YCu$_2$O$_{8+\delta}$, and La$_2$CuO$_4$ as a function of polarization and excitation energy {using samples of the latest generation. From the raw data we derive symmetry-resolved spectra.} The spectral shape in $B_{1g}$ symmetry is found to be nearly universal and independent of the excitation energy. The spectra agree quantitatively with predictions by field theory [\onlinecite{Weidinger:2015}] facilitating the precise extraction of the Heisenberg coupling $J$. {In addition, the asymmetric line shape on the high-energy side is found to be related to amplitude fluctuations of the magnetization. In La$_2$CuO$_4$ alone minor contributions from resonance effects may be identified.} The spectra in the other symmetries are not universal. The variations may be traced back to weak resonance effects and extrinsic contributions. For all three compounds we find support for the existence of chiral excitations appearing as a continuum in $A_{2g}$ symmetry having an onset slightly below $3J$. In La$_2$CuO$_4$ an additional isolated excitation appears on top of the $A_{2g}$ continuum.