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研究了K3C6 0 单晶薄膜在 2 0 0K附近的导带结构 .样品温度为 190K时 ,同步辐射角分辨光电子谱能够观察到[111]方向有规律的能带色散 .而在 2 2 0K附近色散不存在 .这一实验结果与K3C6 0 在 2 0 0K存在取向相变相符合 .用反铁磁Ising模型对实验结果进行了分析 .结果表明 ,K3C6 0 在 2 0 0K的相变是由低温下的一维无序取向结构转变为2 0 0K以上的双取向结构畴与无序分子 (约占 40 % )的混合
The conduction band structure of K3C60 single crystal thin film near 200 K was investigated. The angular band-gap dispersion in the [111] direction was observed by synchrotron radiation angle-resolved photoelectron spectroscopy at 190 K, while the chromatic dispersion near 220 K Which is consistent with that of K3C6 0 at 200 K. The experimental results were analyzed by the antiferromagnetic Ising model.The results show that the phase transition of K3C6 0 at 200 K is caused by the low temperature The one-dimensional disordered orientation structure is transformed into a mixture of disordered domains with more than 200K disordered molecules (about 40%)