The two-dimensional molecular conductor $κ$-(BETS)$_2$Mn[N(CN)$_2$]$_3$ undergoes a sharp metal-to-insulator phase transition at $T_{\rm MI}\approx$ 21 K, which has been under scrutiny for many years. We have performed comprehensive infrared investigations along the three crystallographic directions as a function of temperature down to 10 K, complemented by electron spin resonance and dc-transport studies. The in-plane anisotropy of the optical conductivity is more pronounced than in any other $κ$-type BEDT-TTF or related compounds. The metal-insulator transitions affects the molecular vibrations due to the coupling to the electronic system; in addition we observe a clear splitting of the charge-sensitive vibrational modes below $T_{\rm MI}$ that evidences the presence of two distinct BETS dimers in this compound. The Mn[N(CN)$_2$]$_3^-$ layers are determined by the chain structure of the anions resulting in a rather anisotropic behavior and remarkable temperature dependence of the vibronic features. At low temperatures the ESR properties are affected by the Mn$^{2+}$ ions via $π$-$d$-coupling and antiferromagnetic ordering within the $π$-spins: The $g$-factor shifts enormously with a pronounced in-plane anisotropy that flips as the temperature decreases; the lines broaden significantly; and the spin susceptibility increases upon cooling with a kink at the phase transition.
Ambient pressure Dirac electron system in quasi-two-dimensional molecular conductor $α$-(BETS)$_2$I$_3$
研究了准二维分子导体$α$ -（BETS）$_2$ I $_3$在常压下的精确晶体结构和电子态.该分子固体的电子电阻率在$T_{MI}$ =50 K时显示出金属-绝缘体（MI）交叉。我们的X射线衍射和$^{13}$ C核磁共振实验表明，$α$ -（BETS）$_2$ I $_3$保持低于$T_{MI}$的反转对称性。第一性原理计算发现了一对各向异性的狄拉克锥在一般的k点，与费米能级的简并接触点。在这个系统中的绝缘状态的起源是一个小的能隙~2 meV的自旋轨道相互作用打开。Z $_2$拓扑不变量表明该系统是一个弱拓扑绝缘体。结果表明，$α$ -（BETS）$_2$ I $_3$是一种很有前途的研究二维Dirac电子体系的材料.
First-principles study of the effective Hamiltonian for Dirac fermions with spin-orbit coupling in two-dimensional molecular conductor $α$-(BETS)$_2$I$_3$
采用第一性原理密度泛函理论（DFT）方法研究了准二维分子导体$α$ -（BETS）$_2$ I $_3$ [= $α$ -（BEDT-TSeF）$_2$ I $_3$ ]在30 K低温下的Dirac电子.我们提供了一个紧束缚模型与分子间的转移能量从最大本地化的Wannier函数，其中相关的转移积分的数量是相对较大的，由于Se $p$轨道的离域字符评估。自旋-轨道耦合产生一个奇异的绝缘状态，间接带隙约为2毫电子伏。我们用一个靠近费米能级的狄拉克锥分析了能谱，得到了一个有效的含位势的哈密顿量，它再现了由DFT能带结构得到的能谱。
Dynamics of ethylene groups and hyperfine interactions between donor and anion molecules in $λ$-type organic conductors studied by $^{69,71}$Ga-NMR spectroscopy
ESR Investigations of the Magnetic Anisotropy in $κ$-(BETS)$_2$Mn[N(CN)$_{2}$]$_3$
Universität Stuttgart（斯图加特大学）；Helmholtz-Zentrum Dresden-Rossendorf（德累斯顿-罗斯多夫亥姆霍兹中心）；Federal Research Center of Problems of Chemical Physics and Medical Chemistry, Russian Academy of Sciences（俄罗斯科学院化学物理与医学化学问题联邦研究中心）
Ambient-Pressure Organic Dirac Electron State in $α$-(BETS)$_2$AuCl$_2$
Graduate School of Science and Engineering, Saitama University（埼玉大学理工学研究科）；Research and Development Bureau, Saitama University（埼玉大学研发局）；Institute for Solid State Physics, University of Tokyo（东京大学固体物理研究所）
$^{13}$C NMR observation of a nonmagnetic charge-ordered state in the organic conductor $κ$-(ET)$_{2}$Hg(SCN)$_{2}$Cl
University of Tokyo（东京大学）；The Institute for Solid State Physics, University of Tokyo（东京大学固体物理研究所）；Institute of Problems of Chemical Physics RAS（俄罗斯科学院化学物理问题研究所）；The Institute for Quantum Matter and the Department of Physics and Astronomy, The Johns Hopkins University（约翰斯·霍普金斯大学量子物质研究所及物理与天文学系）；Max Planck Institute for Solid State Research（马克斯·普朗克固体研究所）；University of Stuttgart（斯图加特大学）；Department of Advanced Materials Science, University of Tokyo（东京大学先进材料科学系）
Shubnikov-de Haas effect and Yamaji oscillations in the antiferromagnetically ordered organic superconductor k-(BETS)2FeBr4: A Fermiology study
在有机超导体$κ$ -（BETS）$_2$ FeBr $_4$中观察到了Shubnikov-De Haas效应（SdH）和角相关磁电阻振荡（AMRO）。与其同构化合物$κ-(BETS)$ _2 $FeCl$ _4 $, SdH oscillations, for fields perpendicular to the conducting planes, reveal three Fermi Surface (FS) closed orbits $ α $, $ β $, and $ γ $ whose cross sectional areas are 19.8 %, 99.9 %, and 2.4 % of the first Brillouin zone, respectively. The conduction electron effective masses were found to be: $ μ_α =（4.7 \pm 0.2）$ m$ _e $, $ μ_β =（8.0 \pm 1.0）$ m$ _e $, and $ μ_γ =（2.0 \pm 0.2）$ m$ _e $. The observation of a $ γ $ orbit is not expected from band structure calculations, $ μ_β $ is …
