Crystal structure of the spin-Peierls compound α′-(BEDT–TTF)2Ag(CN)2 at high pressure and low temperature
Crystal structure of the spin-Peierls compound α′-(BEDT–TTF)2Ag(CN)2 at high pressure and low temperature
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自旋 Peierls 化合物 α′-(BEDT–TTF)2Ag(CN)2 在高压和低温下的晶体结构
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
P. Day
中科院分区：
文献类型：
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作者：
P. Guionneau;J. Gaultier;M. Rahal;G. Bravic;J. Mellado;D. Chasseau;L. Ducasse;M. Kurmoo;P. Day
用单晶X射线衍射法测定了α′-（BEDT-TTF）_2Ag（CN）_2 [BEDT-TTF =双（亚乙基二硫代）四硫富瓦烯]在8 kbar（295 K）和260 K（1 bar）下的晶体结构，该晶体在7 K下具有自旋-Peierls相变和超导-半导体相变。通过在298 K下增加压力和在环境压力下降低温度来研究结构转变。其特征在于B参数加倍，并且伴随着分子间的电荷转移，导致不等价的BEDT-TTF分子沿沿着a轴和b轴交替。该晶体具有相同的等温压缩性以上和以下的过渡与极限体积模量（Kv-1）的约。190千巴该盐的结构行为与类质同晶的α′-（BEDT-TTF）_2AuBr_2类似，也表现出自旋-Peierls跃迁。
The crystal structure of α′-(BEDT–TTF)2Ag(CN)2[BEDT–TTF = bis(ethylenedithio)tetrathiafulvalene], which exhibits a spin-Peierls (at 7 K) and a semiconductor-semiconductor transition, was determined above and below the latter phase transition at 8 kbar (295 K) or 260 K (1 bar) by single crystal X-ray diffraction. The structural transition has been studied both by increasing pressure at 298 K and by lowering temperature at ambient pressure. It is characterized by the doubling of the b parameter and it is accompanied by a charge transfer from molecule to molecule, resulting in nonequivalent BEDT–TTF molecules alternating along both a- and b-axes. The crystal has the same isothermal compressibility above and below the transition with a limiting bulk modulus (Kv–1) of ca. 190 kbar. The structural behaviour of this salt is similar to that of the isomorphous α′-(BEDT–TTF)2AuBr2, which also shows a spin-Peierls transition.