Infrared optical properties of the spin-12quantum magnet TiOCl
Infrared optical properties of the spin-12quantum magnet TiOCl
复制标题
自旋12量子磁体TiOCl的红外光学性质
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
Fangcheng Chou
中科院分区：
文献类型：
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作者：
G. Caimi;L. Degiorgi;N. Kovaleva;Peter Lemmens;Fangcheng Chou
我们报告了TiOCl的电动力学响应结果，TiOCl是一种低维自旋1/2量子磁体，在T<Tc l = 67 K时显示出自旋能隙形成。几个选定的红外活性声子的Fano形状表明晶格振动和连续的低频（自旋）激发之间的相互作用。的声子模式参数的温度依赖性延伸在一个广泛的温度范围远高于T C L，表明存在一个扩展的波动制度。在200 K和Tc l之间的温度区间中，存在渐进的维度交叉（从两个到一个），以及从低频率向高频率的谱权重移位。这使我们能够确定一个特征的能量尺度约为430 K，归因于一个伪自旋间隙。
We report results on the electrodynamic response of TiOCl, a low-dimensional spin-½ quantum magnet that shows a spin gap formation for T< T c l = 67 K. The Fano-like shape of a few selected infrared active phonons suggests an interaction between lattice vibrations and a continuum of low-frequency (spin) excitations. The temperature dependence of the phonon mode parameters extends over a broad temperature range well above T c l , indicating the presence of an extended fluctuation regime. In the temperature interval between 200 K and T c l , there is a progressive dimensionality crossover (from two to one), as well as a spectral weight shift from low towards high frequencies. This allows us to identify a characteristic energy scale of about 430 K, ascribed to a pseudo-spin-gap.