Theory of Coexisting Charge and Spin-Density Waves in (TMTTF)_2Br, (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4

TL;DR

This paper develops a microscopic theory explaining the coexistence of unconventional spin-density waves and charge-density waves in certain organic conductors, emphasizing the roles of Coulomb interactions, lattice structure, and band filling.

Contribution

It introduces a comprehensive theoretical model that accounts for strong Coulomb interactions, lattice effects, and anisotropy to explain CDW-SDW coexistence in these materials.

Findings

Unconventional SDWs coexist with CDWs in the studied compounds.

The theory highlights the importance of Coulomb interactions and lattice effects.

Provides a framework for understanding CDW-SDW coexistence in organic conductors.

Abstract

Recent experiments indicate that the spin-density waves (SDWs) in (TMTTF)_2Br, (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4 are highly unconventional and coexist with charge-density waves (CDWs). We present a microscopic theory of this unusual CDW-SDW coexistence. A complete understanding requires the explicit inclusion of strong Coulomb interactions, lattice discreteness, the anisotropic two-dimensional nature of the lattice, and the correct bandfilling within the starting Hamiltonian.