准一维无序体系电子局域化及输运特性  

Characteristics of electronic localization and transportation in quasi-one-dimensional disordered systems

作　　者：宋招权[1] 徐慧[1] 马松山[1] 刘小良[1] 

机构地区：[1]中南大学物理科学与技术学院,湖南长沙 410083

出　　处：《中南大学学报（自然科学版）》2011年第1期125-129,共5页Journal of Central South University:Science and Technology

基　　金：高等学校博士点专项科研基金资助项目(20070533075);湖南省科技计划项目(2009FJ3004)

摘　　要：在单电子紧束缚近似下,利用多对角全随机厄米矩阵算法,结合负本征值理论和无限阶微扰理论及传输矩阵方法,研究准一维多链无序体系中电子波函数局域化特性及其电子输运特性。研究结果表明:由于格点能量无序,准一维多链无序体系电子波函数呈现出局域化特性;格点能量无序度减小会导致在中间能区发生退局域化现象,表现为在中间能区电子波函数的局域长度大于体系格点数,即出现扩展态,且出现扩展态的能量区间随着无序度的减小而增大的趋势;同时,随着链数的增加,体系有向退局域化方向发展的趋势;在中间能区电子输运透射系数较大,而在低能区及高能区透射系数较小,同时,格点能量无序与维度效应对体系的电子输运存在竞争效应,当体系格点数及链数一定时,体系的透射系数随着格点能量无序度的增大而减小,而当体系格点数及格点能量无序度一定时,准一维多链无序体系的透射系数随着体系链数的增大而增大。Based on a tight-binding disordered model describing a single electron band, a model of quasi-one- dimensional disordered systems with several chains was established using the negative eignvalue theory, infinite order perturbation theory and transfer matrix method. The characteristics of electronic localization and transportation in quasi-one-dimensional disordered systems with several chains were discussed. The results indicate that the electronic states of the quasi-one-dimensional disordered systems are localized due to energy disorder of the lattices. The localization length increases with the decrease of the strength of energy disorder of the lattices. At the energy band center, there exist some extent states whose localization lengths are lager than that of the atoms of the chains in weak disorder. Meanwhile, with the increase of the number of the chains, the delocalization can be found. In addition, the transmission coefficient of electron transportion in quasi-one-dimensional disordered system is much higher in the energy band center than that in high and low energy region, and decreases with the increase of the energy disorder degree of the lattices, but increases with the increase of the number of the chains.

关 键 词：准一维无序体系 电子局域化 电子输运 

分 类 号：O482.4[理学—固体物理] TB303[理学—物理]