Thermoelectric power in one-dimensional Hubbard model

TL;DR

This study investigates the thermoelectric power in the one-dimensional Hubbard model, revealing how strong correlations and electron density influence its behavior, including sign changes and magnitude variations across temperatures.

Contribution

It provides a detailed analysis of thermoelectric power using exact diagonalization, highlighting the effects of electron density and interactions in a 1D Hubbard model.

Findings

Sign change of S at n_0=0.73±0.07 due to correlations

S becomes large near half-filling for strong U

S decreases with increasing temperature

Abstract

The thermoelectric power S is studied within the one-dimensional Hubbard model using the linear response theory and the numerical exact-diagonalization method for small systems. While both the diagonal and off-diagonal dynamical correlation functions of particle and energy current are singular within the model even at temperature T>0, S behaves regularly as a function of frequency $\omega$ and T. Dependence on the electron density n below the half-filling reveals a change of sign of S at n_0=0.73+/-0.07 due to strong correlations, in the whole T range considered. Approaching half-filling S is hole-like and can become large for U>>t although decreasing with T.