A Lattice Model of Intercalation

TL;DR

This paper develops a lattice model for ion intercalation in crystals, analyzing thermodynamics, phase diagrams, and possible phase transitions, including phase separation and superfluid-like states, using mean field and pseudospin formalisms.

Contribution

It introduces a mean field lattice model incorporating electron-ion interactions and ion hopping, revealing new phase behaviors such as modulated phases and superfluid-like states.

Findings

Effective ion interactions can cause phase separation.

Modulated phases depend on electron band filling.

High ion transfer parameters lead to superfluid-like states.

Abstract

The thermodynamics of the lattice model of intercalation of ions in crystals is considered in the mean field approximation. Pseudospin formalism is used for the description of interaction of electrons with ions and the possibility of hopping of intercalated ions between different positions is taken into account. Phase diagrams are built. It is shown that the effective interaction between intercalated ions can lead to phase separation or to appearance of modulated phase (it depends on filling of the electron energy band). At high values of the parameter of ion transfer the ionic subsystem can pass to the superfluid-like state.