Thermodynamic properties of a Hubbard model on a cubic cluster - exact diagonalization study at quarter filling

TL;DR

This paper investigates the thermodynamic and magnetic properties of a cubic Hubbard cluster at quarter filling using exact diagonalization, revealing insights into specific heat, susceptibility, and spin correlations.

Contribution

It provides a detailed analysis of thermodynamic quantities and magnetic behavior of a zero-dimensional Hubbard model with exact numerical methods.

Findings

Identification of local maxima in specific heat and susceptibility

Analysis of Schottky anomalies in thermodynamic behavior

Insights into magnetic correlations at quarter filling

Abstract

We study the thermodynamics of a zero-dimensional, cubic cluster described with a Hubbard Hamiltonian, focusing our interest on the magnetic properties. The range in which the studied cluster is paramagnetic is considered. The results are obtained by means of exact numerical diagonalization. Such thermodynamic quantities as entropy, specific heat, magnetic susceptibility, spin-spin correlations and double occupancy are discussed. Particular emphasis is put on the behaviour of local maxima of specific heat and susceptibility, which are analysed in terms of Schottky anomalies.