Phase competitions and coexistences in quasi-one-dimensional molecular conductors: exact diagonalization study

TL;DR

This study uses exact diagonalization to explore how inter-chain interactions and lattice effects influence phase competition and coexistence in quasi-one-dimensional molecular conductors, revealing sensitive dependencies on various parameters.

Contribution

It provides a detailed analysis of phase competition in a quasi-one-dimensional model considering electron-lattice coupling, inter-chain Coulomb interaction, and lattice anharmonicity, using exact diagonalization.

Findings

Critical behavior among lattice tetramerized states is highly sensitive to inter-chain Coulomb interaction.

Lattice anharmonicity and intrinsic dimerization significantly influence phase stability.

Strong correlations and reduced dimensionality create a delicate balance among competing states.

Abstract

We investigate ground state properties of a quasi-one-dimensional electron-lattice coupled model for quarter-filled molecular conductors. The effective one-dimensional extended Hubbard model coupled to adiabatic lattice degree of freedom is derived by the inter-chain mean-field approximation and solved by Lanczos exact diagonalization method. We find that the critical behavior among lattice tetramerized states with different charge-lattice ordered patterns is sensitively affected by the inter-chain Coulomb interaction, lattice anharmonicity, and intrinsic dimerization. This indicates a subtle balance between these states originating from strong correlation and reduced dimensionality.