一维二元非对角关联无序体系跳跃电导特性

Characteristics of hopping conductivity in one-dimensional binary disordered system with off-diagonal correlations

在单电子紧束缚无序模型基础上,建立了一维二元关联无序体系电子跳跃输运直流电导模型,并推导了其直流电导公式,通过计算其直流电导率,探讨了格点能量无序度、非对角关联及温度、外场对体系跳跃电导的影响.计算结果表明,一维二元无序体系的直流电导率随着格点能量无序度的增大而减小;当引入非对角关联时,体系出现退局域化现象,从而使体系的直流电导率增大;温度对体系的电子输运的影响表现为体系的直流电导率随温度的升高而增大;在外加电场的调制下,体系的直流电导率在强场区随电场强度增加而增长很快,呈现出非欧姆定律特性,但在弱场区外场的作用不明显.

Based on a tight-binding disordered model describing a single electron band, we establish a model of electronic transport in one-dimensional binary disordered systems with off-diagonal correlations, and derive the dc conductance formula. By calculating the dc conductivity, the function of disorder and off-diagonal correlations in electronic transport are analyzed, and the relationships between electric field and conductivity and between temperature and conductivity are studied. The results indicate that the conductivity of the systems decreases with the increase of the degree of lattices energy disorder, and off-diagonal correlations lead to delocalization and enhance the electrical conductivity of system. The model also quantitatively explains the temperature and electric field dependence of the conductivity of systems, that is, the dc conductivity of the systems increases with the increasing of temperature and electric field.