An explanation of anisotropy in electrical conductivity of V_2O_5 due to overlap integrals

摘要

The crystal structure of V2O5 is orthorhombic, the atomic arrangement being as shown in Fig. 1. The characteristic behaviour in the electrical conductivity is anisotropic, as shown in Fig. 2; oi,:au:ocK. 180:20:1 in the range 180-300 K [1], where oh, oa, and oc denote the electrical conductivity along the crystal axes b, a and c, respectively. The cause of the anisotropic electrical conductivity is uncertain. This letter gives a quantitative explanation of the anisotropy from the viewpoint of the difference in the magnitude of the overlap integrals between the orbital wave functions of electrons locating in atoms neighbouring towards the direction of the a, b or c axis.