Numerical Modelling of the Seebeck Coefficient Within Modified Versions of the Narrow-Band Model

Abstract

This paper is devoted to the development of modifications of the narrow-band model used to analyze the transport coefficient behavior in high-Tc superconductors in the normal state aiming to avoid this model limitations. We have considered possible physically justified ways to change the approximation method for the differential conductivity function, cr(E), and performed the numerical calculations of the temperature dependences of the Seebeck coefficient, S, within proposed approximations. It is shown that proposed model modifications make it possible to fix the problem of an incorrect description of the $S$($T$) dependences for heavily doped samples in a low temperature range. Introducing into the narrow-band model a smoothing and a temperature dependence of the σ($E$) function allowed us to obtain an excellent agreement of the experimental and calculated results in a wide temperature range.