广义布洛赫方法的应用:低维材料物性的非均匀应变调控  

Application of generalized Bloch method:Strain engineering of low dimensional materials through inhomogeneous strains

作　　者：张东波 魏苏淮 Dongbo Zhang;Suhuai Wei(College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China;Beijing Computational Science Research Center,Beijing 100193,China)

机构地区：[1]北京师范大学核科学与技术学院,北京100875 [2]北京计算科学研究中心,北京100193

出　　处：《科学通报》2021年第6期674-684,共11页Chinese Science Bulletin

基　　金：国家自然科学基金(11991060,11674022,11874088);中央高校基本科研业务费专项资助。

摘　　要：低维材料的结构灵活性以及它们的电子性质对应变灵敏的响应,使得应变调控成为优化低维材料物性的一个重要手段.本文主要介绍了非均匀结构变形下低维材料物性调控的量子力学模拟方法,即广义布洛赫方法.通过考虑螺旋和旋转对称性,广义布洛赫方法能够以较小的计算代价处理扭曲和弯曲两种基本的非均匀结构变形.本文还介绍了该方法的一些具体应用.由于扭曲和弯曲涉及低维材料在多方面的应用,如挠曲电、柔性电子学、自旋电子学等,广义布洛赫方法在这些方面能发挥重要作用.Due to their special structural morphologies,low dimensional materials are in nanometer scale in zero,one or two dimensions.This feature offers them superior structural flexibility.This characteristic,together with their excellent electronic property response to mechanical deformation,makes strain engineering an important way to optimize the physical properties of materials.Because in low dimension,structural deformations are usually inhomogeneous,the standard electronic and phonon calculation methods formulated via translation under the periodic boundary conditions encounter fundamental difficulties.A fresh approach in this aspect is called for rapidly.In this paper,the essential idea of the generalized Bloch method is introduced,in the context of a tight-binding treatment of electrons.This special method makes use of the helical symmetry and rotational symmetry to deal with the two fundamental non-uniform structural deformations,i.e.,torsion and bending.In this way,the atomistic simulation of the deformed structures can still be carried out through a relatively small repeating cell.Such treatment enables the realistic atomistic quantum mechanical simulations in a viable manner.In practice,this new method is implemented into the so-called density-functional tight-binding(DFTB)calculation,an approach widely used in the material computation today.We note that the utility of DFTB brings us several benefits.First of all,the self-consistent field improves the calculation accuracy to be compatible with first-principles calculations.Next,the capability to deal with spin freedoms of DFTB enables us to study the strain tunable properties of spin-polarized electronic states.We illustrate the application of the generalized Bloch method with several examples that can be categorized into"strain tunable electronic properties","spatial manipulation of dopants in semiconductor nanowires",and"strain engineering of phonon properties".We also have a vision that the generalized Bloch method shall have important application in more

关 键 词：低维材料 广义布洛赫方法 应变调控 扭曲 弯曲 

分 类 号：TB34[一般工业技术—材料科学与工程]