异形介观体系电子输运计算的一种简便处理方案  

A Simple Strategy for Electronic Transport Calculation in Irregular Shaped Materials

作　　者：成淑光[1] CHENG Shuguang(Department of Physics,Northwest University,Xi'an 710069,China)

机构地区：[1]西北大学物理系,陕西西安710069

出　　处：《山西大学学报（自然科学版）》2022年第3期649-655,共7页Journal of Shanxi University(Natural Science Edition)

基　　金：陕西省自然科学基金(2019JM-187)。

摘　　要：介观体系的电子输运是凝聚态物理中探索材料新奇电子态性质的重要手段,也为设计未来微纳电子器件提供理论依据。数值计算中通常采用紧束缚模型来处理高于零维(量子点)的自由电子体系:比如电子气、蜂窝格子等二维材料和三维导体、拓扑半金属、拓扑绝缘体等。但对于形状不规则的样品,通常需要处理复杂的体系哈密顿和巨大的计算量。文章介绍了一种基于紧束缚模型处理二维、三维电子体系的简便方案,将体系的尺寸参数引入到近邻耦合系数中,从而极大地简化了体系哈密顿,也减少了计算量。此外,以纺锤形、瓶颈形二维、环形三维电子气为例,我们用非平衡格林函数方法计算了异形介观体系的电子输运性质。该方法广泛适用于计算各种三维材料的电子能带结构性质和输运性质。Electronic transport in mesoscopic systems is an important issue for investigating novel electronic states.It provides theoretical supports for future micro-and nano-electronic devices.In traditional numerical calculations,tight-binding model is usually adopted to study systems as two-dimensional systems(electron gas,graphene,and etc.)and three-dimensional systems(conductors,topological insulators,topological semimetals and etc.).For irregular shaped samples,complex Hamiltonian and huge numerical simulation are usually needed.Here,a simple strategy based on tight-binding model is proposed to deal with two-dimensional and three-dimensional systems by mapping the sample shaped into the nearest coupling.Thus,a significantly simpler Hamiltonian is used and the low computation consumption is satisfied.Taking a fusiform and a bottleneck shaped two-dimensional gas system and three-dimensional AB ring as examples,we have studied the electronic transport of irregular shaped samples by using the non-equilibrium Green’s function method.The presented method also works for the electronic band structure and transport properties of other three-dimensional materials.

关 键 词：电子气 电子输运 量子干涉 

分 类 号：O413[理学—理论物理]