Title: Stability of correlated insulating states in molecular conductors from first-principles calculation Show Chinese title

Title: 从头计算方法研究分子导体中相关绝缘态的稳定性

Abstract: Electronic properties of molecular conductors exhibiting antiferromagnetic (AFM) spin order and charge order (CO) owing to electron correlation are studied using first-principles density functional theory calculations. We investigate two systems, a quasi-two-dimensional Mott insulator $\beta^\prime$-(BEDT-TTF)$_{2}$ICl$_{2}$ with an AFM ground state, and several members of quasi-one-dimensional (TMTTF)$_2$$X$ showing CO. The stabilities of the AFM and CO states are compared between the use of a standard exchange-correlation functional based on the generalized gradient approximation and that of a range-separated hybrid functional; we find that the latter describes these states better. For $\beta^\prime$-(BEDT-TTF)$_{2}$ICl$_{2}$, the AFM order is much stabilized with a wider band gap. For (TMTTF)$_2$$X$, only by using the hybrid functional, the AFM insulating state is realized and the CO states coexisting with AFM order are stable under structural optimization, whose stability among different \textit{X} shows the tendency consistent with experiments. Show Chinese abstract

Abstract: 研究了由于电子关联而表现出反铁磁（AFM）自旋有序和电荷有序（CO）的分子导体的电子性质。利用从头算密度泛函理论计算，我们研究了两个体系：具有反铁磁基态的准二维Mott绝缘体$\beta^\prime$-(BEDT-TTF)$_{2}$ICl$_{2}$，以及一些具有一维特性的(TMTTF)$_2$$X$ 表现出电荷有序的成员。比较了使用基于广义梯度近似的标准交换-关联泛函与范围分离杂化泛函时AFM和CO态的稳定性；我们发现后者能更好地描述这些状态。 对于$\beta^\prime$-(BEDT-TTF)$_{2}$ICl$_{2}$，反铁磁序得到了极大稳定，并且带隙更宽。 对于(TMTTF)$_2$$X$ ，只有通过使用杂化泛函，才能实现反铁磁绝缘态，并且在结构优化下，与反铁磁序共存的电荷有序态是稳定的，不同\textit{X}之间的稳定性表现出与实验一致的趋势。