Two-dimensional radical-cationic Mott insulator based on an electron donor containing neither a tetrathiafulvalene nor tetrathiapentalene skeleton
Two-dimensional radical-cationic Mott insulator based on an electron donor containing neither a tetrathiafulvalene nor tetrathiapentalene skeleton
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基于既不包含四硫富瓦烯也不包含四硫五烯骨架的电子给体的二维自由基-阳离子莫特绝缘体
DOI：
10.1039/d0ce00878h
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发表时间：
2020
期刊：
影响因子：
3.1
通讯作者：
Yamada Jun-ichi
中科院分区：
文献类型：
--
作者：
Kadoya Tomofumi;Sugiura Shiori;Tahara Keishiro;Higashino Toshiki;Kubo Kazuya;Sasaki Takahiko;Takimiya Kazuo;Yamada Jun-ichi
报道了一种新的自由基-阳离子Mott绝缘体θ-（BEDT-BDT）PF 6（BEDT-BDT：benzo [1，2-g：4，5-g ′] bis（thieno [2，3-B][1，4] dithiin））的结构和物理性质.晶体结构属于单斜晶系，供体/阴离子比为1：1。 基于这种组成，盐被认为是半填充的莫特绝缘体，其中BEDT-BDT分子形成θ模式排列。由于强的电子关联，电阻率的温度依赖性表现出半导体行为。静态磁化率首先遵循居里-外斯定律下降到15 K，但随后遵循二维（2D）三角海森堡模型与J = 7.5 K低于15 K。即使在2K下，这种盐也是顺磁性的，没有形成磁性有序。紧束缚带计算揭示了一个二维费米面。值得注意的是，θ-（BEDT-BDT）PF 6形成不含任何1，3-二硫醇-2-亚基单元的2D电子结构，不像四硫富瓦烯和四硫并环戊二烯供体。
We report the structure and physical properties of a new radical–cationic Mott insulator θ-(BEDT-BDT)PF6 (BEDT-BDT: benzo[1,2-g:4,5-g′]bis(thieno[2,3-b][1,4]dithiin)). The crystal structure belongs to a monoclinic system with a 1 : 1 donor/anion ratio. Based on this composition, the salt is considered a half-filled Mott insulator, in which the BEDT-BDT molecules form a θ mode arrangement. Owing to the strong electron correlation, the temperature dependence of the resistivity exhibits semiconducting behaviour. The static magnetic susceptibility first follows the Curie–Weiss law down to 15 K, but then follows the two-dimensional (2D) triangular Heisenberg model with J = 7.5 K below 15 K. Even at 2 K, this salt is paramagnetic and no magnetic order is formed. The tight-binding band calculation reveals a 2D Fermi surface. It is remarkable that θ-(BEDT-BDT)PF6 forms a 2D electronic structure without any 1,3-dithiol-2-ylidene units, unlike tetrathiafulvalene and tetrathiapentalene donors.