Effects of Disorder on Charge Orderings and Superconductivity in the System of Coexisting Itinerant Electrons and Local Pairs

TL;DR

This paper investigates how diagonal disorder influences phase diagrams and thermodynamic properties in a system with coexisting itinerant electrons and local pairs, revealing various ordered and phase-separated states.

Contribution

It introduces a comprehensive analysis of disorder effects on charge orderings and superconductivity in a mixed electron-local pair system, highlighting the emergence of multiple phases.

Findings

Disorder induces transitions between superconducting, charge density wave, and nonordered phases.

Multiple phase-separated states are stabilized depending on disorder strength and interactions.

The model predicts rich phase diagrams with various coexisting and competing orders.

Abstract

We study the phase diagrams and thermodynamic properties of a system of coexisting itinerant electrons and local pairs (LP), in the presence of diagonal disorder. The model considered takes into account both the charge exchange couplings, responsible for superconducting orderings, and the density-density interactions, which can stabilize charge ordered states in the system. Depending on the strength of the random on-site potential, the interactions and the particle concentrations the model is found to exhibit several various phases, including the homogeneous ones: superconducting (SC), charge density wave (CDW) and nonordered (NO), as well as the phase separated states (CDW-SC and CDW-NO).