并苯分子结的热电性质  

Thermoelectric properties of acene molecular junctions

作　　者：谢忠祥[1] 喻霞[1] 贾聘真 陈学坤 邓元祥[1] 张勇[1] 周五星 Xie Zhong-Xiang;Yu Xia;Jia Pin-Zhen;Chen Xue-Kun;Deng Yuan-Xiang;Zhang Yong;Zhou Wu-Xing(School of Science,Hunan Institute of Technology,Hengyang 421002,China;School of Mathematics and Physics,University of South China,Hengyang 421001,China;School of Materials Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南工学院理学院,衡阳421002 [2]南华大学数理学院,衡阳421001 [3]湖南科技大学材料科学与工程学院,湘潭411201

出　　处：《物理学报》2023年第12期177-186,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12074115,11874145,11904161);湖南省自然科学基金(批准号:2021JJ30202,2021JJ30203,2022JJ30222)资助的课题。

摘　　要：通过运用非平衡格林函数方法,研究了基于并苯连接石墨烯纳米带的分子结的热电性质.主要考虑了并苯分子长度、并苯分子与石墨烯纳米带电极的接触位置对并苯分子结热电参量的影响.结果发现并苯分子结最大热电优值(ZT_(max))对应的热导中声子贡献往往占据主导地位.当并苯分子的长度增加,声子热导单调减少,最终变得与并苯分子长度几乎无关.当并苯分子与石墨烯纳米带左(右)电极的中(上)部接触时,对应的ZT_(max)是最高的,然而当并苯分子与石墨烯纳米带左(右)电极的中(中)部接触时,对应的ZT_(max)是最低的.当温度增加时,ZT_(max)有单调增加的趋势,无关于接触位置.随着并苯分子长度的增加,ZT_(max)对应化学势的位置越靠近本征费米能级.以上发现能对未来设计基于并苯分子结的热电器件提供有价值的参考.By using non-equilibrium Green’s function method,we investigate the thermoelectric properties of molecular junctions based on acene-linked graphene nanoribbons.The effects of the length of the acene molecule,the contact position between the acene molecule and graphene nanoribbon electrode on the thermoelectric parameters are mainly considered in this work.It is found that the phonon contribution is dominant in the thermal conductance corresponding to the maximum of the thermoelectric figure of merit(ZT_(max)).As the length of the acene molecule increases,the phonon thermal conductance decreases monotonically,and eventually becomes almost independent of the acene molecule’length.When the acene molecules contact the middle(upper)part of the left(right)electrode of graphene nanoribbon,the corresponding ZT_(max)is the highest.However,when the acene molecules contact the middle(middle)part of the left(right)electrode of graphene nanoribbons,the corresponding ZT_(max)is the lowest.As the temperature increases,ZT_(max)has a monotonically increasing tendency,regardless of the contact position.With the increase of the length of the acene molecule,the chemical potential corresponding to ZT_(max)becomes closer to the intrinsic Fermi level.The above findings may provide the valuable reference for the future design of thermoelectric devices based on the acene molecular junctions.

关 键 词：热输运 电输运 热电性质 并苯分子结 

分 类 号：O469[理学—凝聚态物理]