一维无序体系的交流跳跃导电  

Alternating current hopping conductivity studies on one-dimensional disordered systems

作　　者：徐慧[1] 宋袆璞 

机构地区：[1]中南大学应用物理系,长沙410083

出　　处：《物理学报》2002年第8期1798-1803,共6页Acta Physica Sinica

摘　　要：建立了electron phonon field(EPF)电子隧穿电导模型 ,推导了一维无序体系新的交流电导公式 .通过计算具有2 0 0 0 0— 6 5 0 0 0个格点的无序体系的交流电导率 ,分析了交流电导率与温度及外场频率的关系 ,讨论了无序度对交流电导的影响 .计算结果表明 ,无序体系的交流电导率随外场频率的增加而近似线性的增大 ;无序体系在低温区出现了负微分电阻特性 ,电导率随温度的升高而增大 ,在高温区电导率随温度的升高而减小 ;无序度对无序体系的交流电导影响明显 :在低温区 ,无序度越小 ,体系的电导率越大 ;在高温区 ,适当增大无序度 ,有利于电子共振隧穿条件的形成 ,提高体系的电导率 .但是如果无序度过大 。A electron\|phonon\|field conductance model of electron tunneling transfer is set up, and a new alternating current conductance formula in one dimensional disordered system is derived. By calculating the alternating current conductivity, the relationship among the electric field、temperature and conductivity is analyzed, and the effect of disordered degree on the alternating current conductance is discussed. The result shows that the conductivity of the disordered system linearly increases with rising frequency of the electric field. In the low temperature region, the disordered system shows the characteristic of negative differential dependence of resistance and temperature. On the contrary, its conductivity decreases with rising temperature in the high\|temperature region. The disordered degree has obvious influence on the alternating current conductance. The alternating current conductivity is great when the disordered degree is weak in the low\|temperature region. However, when the disordered degree is raised properly in the high\|temperature region, it is advantageous to form the electron tunneling transfer and to increase the conductivity of the system. But when the disordered degree is overly great, the alternating current conductivity becomes small.

关 键 词：一维无序体系 电子隧穿 跳跃电导 交流电导率 非晶态半导体 有机聚合物 

分 类 号：O482.4[理学—固体物理]