Quantitative assessment of the universal thermopower in the Hubbard model

Abstract

As primarily an electronic observable, the room-temperature thermopower S in cuprates provides possibilities for a quantitative assessment of the Hubbard model. Using determinant quantum Monte Carlo, we demonstrate agreement between Hubbard model calculations and experimentally measured room-temperature S across multiple cuprate families, both qualitatively in terms of the doping dependence and quantitatively in terms of magnitude. We observe an upturn in S with decreasing temperatures, which possesses a slope comparable to that observed experimentally in cuprates. From our calculations, the doping at which S changes sign occurs in close proximity to a vanishing temperature dependence of the chemical potential at fixed density. Our results emphasize the importance of interaction effects in the systematic assessment of the thermopower S in cuprates.

High-temperature behaviour of thermopower is special in cuprates, allowing for theory-experiment comparisons. Wang et al. use quantum Monte Carlo to compute high temperature thermopower in the Hubbard model, demonstrating qualitative and quantitative agreement with experiments across multiple cuprate families.