Hubbard pair cluster in the external fields. Studies of the chemical potential

TL;DR

This paper investigates the chemical potential of a two-site Hubbard cluster under external electric and magnetic fields using exact diagonalization, analyzing effects of temperature, Coulomb energy, and electron concentration.

Contribution

It provides a detailed analysis of the chemical potential behavior in a two-site Hubbard model with external fields, including discontinuities in the ground state.

Findings

Discontinuous behavior of chemical potential in the ground state.

Influence of temperature, Coulomb energy, and electron concentration on chemical potential.

Exact diagonalization approach applied to a two-site Hubbard cluster.

Abstract

The chemical potential of the two-site Hubbard cluster (pair) embedded in the external electric and magnetic fields is studied by exact diagonalization of the Hamiltonian. The formalism of the grand canonical ensemble is adopted. The influence of temperature, Hubbard on-site Coulombic energy $U$ and electron concentration on the chemical potential is investigated and illustrated in figures. In particular, a discontinuous behaviour of the chemical potential (or electron concentration) in the ground state is discussed.