Mean-field study of charge order with long periodicity in $\theta$-(BEDT-TTF)${}_2$X

Abstract

Charge ordering phenomenon in $\theta$-(BEDT-TTF)${}_2$X is studied by using 1/4-filled extended Hubbard model on an anisotropic triangular lattice through mean-field approximation. It is found that a metallic charge ordered state with 3-periodicity on lattices (3-fold type charge order) is realized in the realistic parameter region where the nearest neighbor Coulomb interaction V${}_{ij}$ is nearly isotropic. This 3-fold state survives up to high temperatures by estimating the free energy. Insulating state with diagonal or vertical-type charge ordering appears as increasing anisotropy of V${}_{ij}$. Considering the effect of the structural distortion observed in $\theta$-(BEDT-TTF)${}_2$RbZn(SCN)${}_4$ at low temperatures, horizontal-type charge ordered insulating phase tends to be stabilized and the region where 3-fold type exists becomes narrower. Our results are consistent with the metallic state with long periodic charge order which can be related to 3-fold type in $\theta$-(BEDT-TTF)${}_2$RbZn(SCN)${}_4$ at high temperatures and insulating state with horizontal charge order at low temperatures. For $\theta$-(BEDT-TTF)${}_2$CsZn(SCN)${}_4$, we speculate several kinds of charge-ordered states are energetically competing with each other leading to an inhomogeneous state at low temperatures.

arXiv comment7 pages, 9 figures, some typos corrected

References in corpus (8)

• Charge Ordering in Organic ET Compounds
• Charge ordering and antiferromagnetic exchange in layered molecular crystals of the theta type
• Large dielectric constant and giant nonlinear conduction in the organic conductor theta-(BEDT-TTF)_2CsZn(SCN)_4
• Quantum Melting of Charge Order due to Frustration in Two-Dimensional Quarter-Filled Systems
• Deducing correlation parameters from optical conductivity in the Bechgaard salts
• Charge ordering in theta-(BEDT-TTF)_2 X materials
• Dynamical properties of a strongly correlated model for quarter-filled layered organic molecular crystals
• Metal-insulator transition and charge ordering in the extended Hubbard model at one-quarter filling

Cited by in corpus (33)

• Theoretical Aspects of Charge Ordering in Molecular Conductors
• Strong coupling theory of the spinless charges on the triangular lattices: possibility of a new quantum liquid
• Novel Charge Order and Superconductivity in Two-Dimensional Frustrated Lattice at Quarter Filling
• Crystallization and vitrification of electrons in a glass-forming charge liquid
• The Origin of the Charge Ordering and Its Relevance to Superconductivity in $\theta$-(BEDT-TTF)${}_2$X: The Effect of the Fermi Surface Nesting and the Distant Electron-Electron Interactions
• Growth Dynamics of Photoinduced Domains in Two-Dimensional Charge-Ordered Conductors Depending on Stabilization Mechanisms
• Charge Order with Structural Distortion in Organic Conductors: Comparison between θ-(ET)2RbZn(SCN)4 and α-(ET)2I3
• Phase Diagram of Spinless Fermions on an Anisotropic Triangular Lattice at Half-filling
• Charge ordering and coexistence of charge fluctuations in quasi-two-dimensional organic conductors $\theta$-(BEDT-TTF)${}_{2}X$
• Coexistence of distinct charge fluctuations in $\theta$-(BEDT-TTF)${}_2$X
• Charge, Lattice, and Spin Dynamics in Photoinduced Phase Transitions from Charge-Order-Insulator to Metal in Quasi-Two-Dimensional Organic Conductors
• Quantum critical behavior of electrons at the edge of charge order
• Systematic Variations in the Charge-Glass-Forming Ability of Geometrically Frustrated $\theta$-(BEDT-TTF)${}_{2}X$ Organic Conductors
• Effects of Electron-Lattice Coupling on Charge Order in θ-(ET)2X
• Geometrical frustration effects on charge-driven quantum phase transitions
• Emergent Heavy Fermion Behavior at the Wigner-Mott Transition
• Spin and Charge Fluctuations and Lattice Effects on Charge Orders in α-(BEDT-TTF)_2I_3
• Charge Fluctuations in Geometrically Frustrated Charge Ordering System
• Theoretical Aspects of Charge Correlations in $\theta$-(BEDT-TTF)${}_{2}X$
• Enhancement of Spin Susceptibility near Charge-Ordering Transition in a Two-Dimensional Extended Hubbard Model
• Variational Monte Carlo Study of a Spinless Fermion t-V Model on a Triangular Lattice: Formation of a Pinball Liquid
• Long-Period Charge Correlations in Charge-Frustrated Molecular theta-(BEDT-TTF)2X
• Competing Generalized Wigner Crystal States in Moiré Heterostructures
• Collective excitation of a short-range charge ordering in $\theta$-$\mbox{(BEDT-TTF)}_2\mbox{CsZn(SCN)}_4$
• Superconductivity in the vicinity of charge ordered state in organic conductor beta-(meso-DMBEDT-TTF)_2PF_6
• Anomalous 2D-confined electronic transport in layered organic charge-glass systems
• Pinball liquid phase from Hund's coupling in frustrated transition metal oxides
• Multiorbital kinetic effects on charge ordering of frustrated electrons on the triangular lattice
• Superconductivity in the Three-Fold Charge-Ordered Metal of the Triangular-Lattice Extended Hubbard Model
• Microscopic coexistence of superconductivity and charge order in organic superconductor ${\beta }^{\prime \prime }$-(BEDT-TTF)${}_4$[(H${}_3$O)Ga(C${}_2$O${}_4$)${}_3$]$\cdot$C${}_6$H${}_5$NO${}_2$
• Finite Temperature Properties of Geometrically Charge Frustrated Systems
• Particle-Hole Asymmetry and Pinball Liquid in a Triangular-Lattice Extended Hubbard Model within Mean-Field Approximation
• Nonlinear Conduction by Melting of Stripe-Type Charge Order in Organic Conductors with Triangular Lattices