Disordered Systems Electron Transport In Disordered Mechanism Of Action Studies

Disordered materials is one of the most widely existing materials in the nature. In recent years disordered system without periodic configuration has become an important domain of physics of condensed matter and material science due to their potential applications. In all of the world, particular attention has been devoted to the trait of electronic transportation of disordered system.Based on the Anderson's disordered model, and considered the affection of non-diagonal disorder, we set up a new model of one-dimensional disordered system. Then we studied the electronic localization property and the distribution of Femi-energy in disordered system. The result shows that the electronic localization is strengthened and the Femi-energy is declined when non-diagonal disorder is considered. At the same time, integrated Mott's variable range hopping conduction theory and Miller-Abrahams resistor network model, and considered the affection of the electric field and phonon on the electron hopping, an electronic hopping transportation model of one-dimensional disordered system is set up, then direct current and alternating current conductance formulas in one-dimensional disordered system are derived. By calculating the D.C and A.C conductivity, the conductance characteristic of disordered system is analyzed systematically, and by considering different disordered state, the effects of temperature and electric field, especially the effects of disorder on electronic transportation are discussed in detail. The results show that, the D.C and A.C conductivity of disordered system decreases with the increasing of the disorder degree when only considering the diagonal disorder, but the conductivity increases first and then decreases with the increasing of the disorder degree when only non-diagonal disorder is considered, at the same time, the conductivity when only the diagonal disorder is considered is less than the conductivity of non-diagonal disordered system. In both of diagonal and non-diagonal disordered system, the relation between the conductivity of system and disorder degree is similar to non-diagonal disordered system, and it shows that the disorder ofnon-diagonal disorder have much more effect on the conductivity than the diagonal disorder. Besides, the conductivity of both of diagonal and non-diagonal disordered system is bigger than non-diagonal disordered system, but less than diagonal disordered system. It shows that when disorder degree is weak, there is a competing reaction between non-diagonal disorder and diagonal disorder on the conductivity of system. On the one hand, the conductivity of the system decreases with the increasing of the diagonal disorder. On the other hand, the influence of non-diagonal disorder on the conductivity of the system represents that the conductivity increases first and then decreases with the increasing of the disorder degree. And because the conductivity of the system with the non-diagonal disorder is less than the conductivity of the system with the diagonal disorder, so the conductivity of system with both of diagonal and non-diagonal disordered is bigger than non-diagonal disordered system, but less than diagonal disordered system. The disordered system appears the characteristic of negative differential dependence of resistance and temperature in low temperature region, i.e. the conductivity increases with the raising of temperature, but decreases with the raising of temperature in high temperature region. The temperature corresponded to the maximum value of conductivity is lower in non-diagonal disordered system than in diagonal disordered system, that is, the temperature corresponded to the maximum value of conductivity is different from different disordered modality. The D.C conductivity decreases with the increasing of electric field voltage, however the A.C conductivity linearly increases with the raising of frequency of electric field.