Temperature Dependence of Crystal Structures and Band Parameters in Quantum Spin Liquid β′-EtMe3Sb[Pd(dmit)2]2 and Related Materials

Crystals

Kohei Ueda¹  Takao Tsumuraya¹  Reizo Kato¹ 

[1] Condensed Molecular Materials Laboratory, RIKEN, 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan;

关键词: molecular conductor;    quantum spin liquid;    geometrical frustration;    crystal structure;    band calculation;   

DOI  :  10.3390/cryst8030138

来源: DOAJ

【 摘 要 】

In an isostructural series of anion radical salts β′-(Me4-xEtxZ)[Pd(dmit)2]2 (Z = P, As, Sb; x = 0, 1, 2), [Pd(dmit)2]2− units form a two-dimensional Mott insulator layer with a quasi-isosceles triangular lattice. The anisotropy of the triangular lattice is characterized by a ratio of interdimer transfer integrals, t′/t. The crystal structures of EtMe3Sb, Me4Sb, Me4As, and Et2Me2As salts were determined in the range of 5–295 K by the single crystal X-ray diffraction technique. Interdimer transfer integrals, Fermi surface, and band structures at low temperatures were calculated by the tight binding method and the first-principles density-functional theory (DFT) method based on experimentally obtained crystal structures. Interdimer transfer integrals increased with lowering temperature. At 5 K, the ratio t′/t decreased by about 15% from the room temperature value in every salt. The relationship between the transfer integrals and interdimer S⋯S distances indicated that the change of the t′/t value with temperature was due to a thermal contraction, rather than the arch-shaped molecular distortion of the Pd(dmit)2 molecule associated with the cation dependence of t′/t.

【 授权许可】

Unknown