ANOMALOUS DIELECTRIC RESPONSE IN TETRATHIAFULVALENE-PARA-CHLORANIL AS OBSERVED IN TEMPERATURE-INDUCED AND PRESSURE-INDUCED NEUTRAL-TO-IONIC PHASE-TRANSITION
ANOMALOUS DIELECTRIC RESPONSE IN TETRATHIAFULVALENE-PARA-CHLORANIL AS OBSERVED IN TEMPERATURE-INDUCED AND PRESSURE-INDUCED NEUTRAL-TO-IONIC PHASE-TRANSITION
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DOI：
10.1103/physrevb.43.8224
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发表时间：
1991-04-01
影响因子：
3.7
通讯作者：
SAITO, G
中科院分区：
文献类型：
--
作者：
OKAMOTO, H;MITANI, T;SAITO, G
在100 Hz至10 MHz的频率范围内，测量了混合堆叠有机电荷转移晶体四硫富瓦烯-对氯醌的介电常数与温度和压力的关系。 介电响应随温度的降低而显著增加，T（c）= 81 K，其中中性到离子（NI）相变发生。 另一方面，在室温下施加压力，在介电响应的变化是不太显着的，而直流电导率sigma-dc显着增加。 这种动力学响应的Debye型弛豫模型解释。 介电响应的强度与弛豫时间τ和sigma-dc两者密切相关。 这些异常的介电响应归因于中性晶格中的NI畴壁对和离子畴的动力学。
The temperature and pressure dependences of the dielectric constants have been measured on the mixed-stack organic charge-transfer crystal, tetrathiafulvalene-p-chloranil, in a frequency range from 100 Hz to 10 MHz. The dielectric response increases remarkably with decreasing temperature down to T(c) = 81 K, where the neutral-to-ionic (NI) phase transition occurs. On the other hand, with applied pressure at room temperature, the change in the dielectric response is less remarkable, whereas the dc conductivity sigma-dc increases considerably. Such dynamical responses are explained by a Debye-type relaxation model. The strength of the dielectric response is closely correlated with both the relaxation time tau and sigma-dc. These anomalous dielectric responses are attributed to the dynamics of the NI domain-wall pairs and ionic domains in the neutral lattice.