We investigate the anion arrangement effect on the electronic states of various bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) compounds composed of BEDT-TTF layers and counter-anion networks via Raman scattering measurements. The anion vibrational modes and charge-sensitive BEDT-TTF vibrational modes of disordered-anion compounds κ-(BEDT-TTF)₂Cu₂(CN)₃, κ-(BEDT-TTF)₂Ag₂(CN)₃, and (BEDT-TTF)Ag₄(CN)₅, indicate splitting, contrary to the case of non-disordered-anion compounds κ-(BEDT-TTF)₂Ag(CN)[N(CN)₂] and κ-(BEDT-TTF)₂Cu[N(CN)₂]Cl. The splitting behaviors indicate that several possible arrangements of CN bonds exist in the anion networks. These results suggest that the disorder in the anion structures is not directly due to the recently reported charge disproportionation or relaxor-like dielectric response in some κ-type BEDT-TTF compounds. Additionally, in κ-(BEDT-TTF)₂Cu₂(CN)₃, the frequency of the anion mode and the dielectric constant have local maxima at the same temperature. This result suggests that the anion modes are affected by the dielectric responses of the counter cations.

中文翻译：

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阴离子对κ型BEDT-TTF化合物电子态的影响

我们通过拉曼散射测量研究了阴离子排列对各种由BEDT-TTF层和抗衡阴离子网络组成的双（亚乙基二硫代）四硫富瓦烯（BEDT-TTF）化合物的电子态的影响。阴离子振动模式和电荷敏感BEDT-TTF无序阴离子化合物的振动模式κ - （BEDT-TTF）₂的Cu ₂（CN）₃，κ - （BEDT-TTF）₂的Ag ₂（CN）₃，和（ BEDT-TTF）Ag ₄（CN）₅表示分裂，与无序阴离子化合物κ-（BEDT-TTF）₂ Ag（CN）[N（CN）₂]和κ-（BEDT-TTF）₂ Cu [N（CN）₂ ] Cl。分裂行为表明在阴离子网络中存在CN键的几种可能的排列。这些结果表明，阴离子结构的紊乱不是直接由于最近报道的某些κ型BEDT-TTF化合物中的电荷歧化或类似弛豫的介电反应而引起的。另外，在κ-（BEDT-TTF）₂ Cu ₂（CN）_3中，阴离子模式的频率和介电常数在相同温度下具有局部最大值。该结果表明，阴离子模式受抗衡阳离子的介电响应影响。