van Hove scenario and thermopower behavior of the high-Tccuprates

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Abstract
We examine the requirements for a van Hove singularity in the electronic density of states to cause the systematic thermopower behavior observed in the normal state of the cuprate superconductors. We concentrate on the Bi-, Tl-, and Hg-based cuprates which are not complicated by the presence of CuO chains and in which a wide range of doping levels can be achieved. Our calculations, using a simple model for the van Hove singularity, can reproduce the experimental data well, provided a wideband thermopower contribution is also present and provided the singularity remains close to the chemical potential as the carrier concentration varies. © 1996 The American Physical Society.