Interorbital interaction in the one-dimensional periodic Anderson model: A density-matrix renormalization-group study

TL;DR

This study uses density-matrix renormalization-group techniques to analyze how interorbital Coulomb interactions influence spin and charge excitations, entanglement, and ground state configurations in the one-dimensional periodic Anderson model.

Contribution

It provides new insights into the effects of Coulomb interaction $U_{cf}$ on excitation spectra and entanglement structure in the 1D periodic Anderson model, which were previously unexplored.

Findings

Spin gap is smaller than charge gap for low $U_{cf}$.

Reversal of spin and charge gap inequality occurs at higher $U_{cf}$.

Ground state entanglement varies with $U_{cf}$, showing strong entanglement at certain values and site alternation at larger $U_{cf}$.

Abstract

We investigate the effect of the Coulomb interaction, $U_{cf}$, between the conduction and f electrons in the periodic Anderson model using the density-matrix renormalization-group algorithm. We calculate the excitation spectrum of the half-filled symmetric model with an emphasis on the spin and charge excitations. In the one-dimensional version of the model it is found that the spin gap is smaller than the charge gap below a certain value of $U_{cf}$ and the reversed inequality is valid for stronger $U_{cf}$. This behavior is also verified by the behavior of the spin and density correlation functions. We also perform a quantum information analysis of the model and determine the entanglement map of the f and conduction electrons. It is revealed that for a certain $U_{cf}$ the ground state is dominated by the configuration in which the conduction and f electrons are strongly entangled, and the ground state is almost a product state. For larger $U_{cf}$ the sites are occupied alternatingly dominantly by two f electrons or by two conduction electrons.