Competing ground states of metal-halide ladders

TL;DR

This paper explores the complex ground states of metal-halide ladder compounds using a two-band Peierls-Hubbard model, revealing various charge and spin-ordered phases and transitions driven by electronic interactions.

Contribution

It introduces a detailed theoretical analysis of metal-halide ladders, identifying competing charge and spin-ordered states and phase transitions based on numerical phase diagrams.

Findings

Identification of multiple charge- and spin-ordered states

Demonstration of phase transitions between mixed-valent states

Influence of interchain hopping and Coulomb interactions on ground states

Abstract

Based on a symmetry argument, we investigate the ground-state properties of newly synthesized metal-halide ladder compounds (C_8_H_6_N_4_)[Pt(C_2_H_8_N_2_)X]_2_(ClO_4_)_4_ 2H_2_O (X=Cl, Br, I). Employing a fully dressed two-band Peierls-Hubbard model, we systematically reveal possible charge- or spin-ordered states. Numerical phase diagrams demonstrate a variety of competing Peierls and Mott insulators with particular emphasis on the transition between two types of mixed-valent state of Pt^II^ and Pt^IV^ driven by varying interchain hopping integrals and Coulomb interactions.