基于石墨烯电极TCNQ分子结热/电输运性质理论研究  

Theoretical study on heat/electric transport properties of TCNQ molecular junction with graphene electrode

作　　者：刘仪伟 邱乙峰 张蓓[1] LIU Yi-Wei;QIU Yi-Feng;ZHANG Bei(School of Physical Science and Technology,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学物理科学与技术学院,乌鲁木齐830046

出　　处：《原子与分子物理学报》2025年第3期135-140,共6页Journal of Atomic and Molecular Physics

基　　金：自治区科技厅自然科学基金(2021D01C033);国家自然科学基金地区基金(12164046)。

摘　　要：本文采用密度泛函理论和非格林平衡函数,对基于石墨烯电极的7,7,8,8-四氰基苯醌二甲烷(Tetracyanoquinodimethane,TCNQ)分子结热/电输运性质进行系统研究.研究结果表明:随着中心TCNQ分子个数的增加,声子透射系数明显降低,即声子透射行为受到极大抑制.与此同时,电子透射系数也有一定程度的减小.在热/电参数的协同作用下,伴随分子数量的增加分子结热电转换性能呈上升趋势,1TCNQ热电优值(ZT)为0.016,而2TCNQ则上升了1个数量级,ZT值达到0.11.最后,我们对分子结依赖于分子结构个数的自旋输运性质进行研究,发现TCNQ分子结具有显著的自旋过滤效应,其过滤能力随着TCNQ分子数量的增加而增加.该工作可为实验制备分子热电器件提供理论依据和数据支持.The thermal/electrical transport properties of 7,7,8,8-tetracyanoquinodimethane(TCNQ)molecules based on graphene electrodes were systematically studied by density functional theory and non-Green's equilibrium function.The results show that with the change of the number of TCNQ molecules,the phonon transmission coefficient of the system decreases obviously,and the phonon transmission behavior is greatly inhibited.At the same time,electron transport is also inhibited to some extent.With the increase of the number of molecules,the thermoelectric properties of molecular junction are improved.The thermoelectric value(ZT)of 1TCNQ is 0.016,and that of 2TCNQ is increased by one order of magnitude,reaching 0.11.Finally,we studied the spin transport properties of molecular junctions that depend on the number of molecular junctions.We found that TCNQ molecular junctions have a significant spin filtration effect,and the filtration capacity increases with the increase of the number of TCNQ molecules.This work can provide theoretical basis and data support for the experimental preparation of molecular thermoelectric devices.

关 键 词：锯齿状石墨烯纳米带 TCNQ分子 自旋输运性质 自旋过滤效应 

分 类 号：O469[理学—凝聚态物理]