# Quasiperiodicity and valence fluctuation in the spin-1/2 Falicov-Kimball model

## TL;DR

This paper investigates the effects of quasiperiodic structure on valence fluctuations and magnetic response in the spin-1/2 Falicov-Kimball model on a Penrose lattice, revealing continuous valence changes and site-dependent electron behavior.

## Contribution

It introduces a real-space dynamical mean-field approach to study valence fluctuations in a quasiperiodic lattice, highlighting the influence of lattice structure on electron density and magnetic properties.

## Key findings

- Continuous variation of $f$ electron density with level tuning.
- Site-dependent $f$ electron number influenced by Penrose structure.
- Temperature affects magnetic response in the quasiperiodic system.

## Abstract

We study the spin-1/2 Falicov-Kimball model with conduction and localized $f$ electrons on the Penrose lattice using the real-space dynamical mean-field theory. By changing the $f$ electron level, the $f$ electron density at each site changes continuously, in contrast to periodic systems with first-order valence transitions. In the intermediate valence regime, the local $f$ electron number strongly depends on a wider range of the Penrose structure surrounding its lattice site, in spite of the local interaction between the conduction and $f$ electrons. The temperature dependence of the magnetic response is also discussed.