摘要
利用傅里叶滤波法在一维Anderson无序系统中产生了具有幂律谱密度公式s(q)∝q-p形式的长程关联随机能量序列,并利用传输矩阵方法计算了系统中引入了长程关联后的局域长度,同时应用负本征值理论对系统中的电子态密度进行了分析,并分别把计算结果与系统中不具有长程关联时的局域长度与电子态密度进行了比较.结果表明,长程幂律关联的引入对电子态的性质产生了很大的影响,当关联指数p≥2.0时,在系统能带中心范围内发生了部分局域态向退局域态的转变,而同时电子态密度也发生了很大的变化,出现了六个范霍夫奇点,系统的能带范围也相应地得到展宽.
We generated the long-range correlated random energy sequences with the power-law spectral density s s（q）∝q^-p in the one-dimensional Anderson disordered chain, and then investigated the localization length by using the transfer matrix method. The density of electronic states were also analyzed with the help of the negative eigenvalue theory. Then we made a comparison between the results and that of the system which does not have long-range correlations. Our results show that after introducing the long-range correlations in the one-dimensional Anderson disordered chain, the properties of electronic states change greatly, and when the correlation exponent p ≥ 2.0, there exists a localization-delocalization transition at the energy band center. Accordingly, the density of electronic states changes obviously and presents six van Hove singularities, and moreover, the energy band of the system also extends slightly, accompanying the above changes.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第3期1643-1648,共6页
Acta Physica Sinica
基金
湖南省自然科学基金(批准号:05JJ40135)
中南大学文理基金(批准号:0601052)资助的课题.~~
关键词
无序系统
长程关联
局域长度
电子态密度
disordered system, long-range correlations, localization length, density of electronic states
