Geometrical frustration effects on charge-driven quantum phase transitions

Abstract

The interplay of Coulomb repulsion and geometrical frustration on charge-driven quantum phase transitions is explored. The ground state phase diagram of an extended Hubbard model on an anisotropic triangular lattice relevant to quarter-filled layered organic materials contains homogeneous metal, 'pinball' and three-fold charge ordered metallic phases. The stability of the 'pinball' phase occurring for strong Coulomb repulsions is found to be strongly influenced by geometrical frustration. A comparison with a spinless model reproduces the transition from the homogeneous metallic phase to a pinball liquid, which indicates that the spin correlations should play a much smaller role than the charge correlations in the metallic phase close to the charge ordering transition. Spin degeneracy is, however, essential to describe the dependence of the system on geometrical frustration. Based on finite temperature Lanczos diagonalization we find that the effective Fermi temperature scale, T*, of the homogeneous metal vanishes at the quantum phase transition to the ordered metallic phase driven by the Coulomb repulsion. Above this temperature scale 'bad' metallic behavior is found which is robust against geometrical frustration in general. Quantum critical phenomena are not found whenever nesting of the Fermi surface is strong, possibly indicating a first order transition instead. 'Reentrant' behavior in the phase diagram is encountered whenever the 2kF-CDW instability competes with the Coulomb driven three-fold charge order transition. The relevance of our results to the family of quarter-filled materials: theta-(BEDT-TTF)2X is discussed.

15 pages, 11 figures

References in corpus (20)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum Criticality in Heavy Fermion Metals
• Quantum critical scaling of the geometric tensors
• Electronic correlations in the iron pnictides
• Ground-State Fidelity and Bipartite Entanglement in the Bose-Hubbard Model
• 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
• Quantum Melting of Charge Order due to Frustration in Two-Dimensional Quarter-Filled Systems
• Novel Charge Order and Superconductivity in Two-Dimensional Frustrated Lattice at Quarter Filling
• Multisite versus multiorbital Coulomb correlations studied within finite-temperature exact diagonalization dynamical mean-field theory
• 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
• Mott transition in two-dimensional frustrated compounds
• Towards the parameterisation of the Hubbard model for salts of BEDT-TTF: A density functional study of isolated molecules
• Coulomb parameters and photoemission for the molecular metal TTF-TCNQ
• Dynamics of the quantum dimer model on the triangular lattice: Soft modes and local resonating valence-bond correlations
• 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
• Quantum critical behavior of electrons at the edge of charge order
• Direct observation of charge order in triangular metallic AgNiO2 by single-crystal resonant X-ray scattering
• Variational Monte Carlo Study of a Spinless Fermion t-V Model on a Triangular Lattice: Formation of a Pinball Liquid

Cited by in corpus (15)

• Phases of correlated spinless fermions on the honeycomb lattice
• Combined topological and Landau order from strong correlations in Chern bands
• Phase diagram of the triangular extended Hubbard model
• Emergent Heavy Fermion Behavior at the Wigner-Mott Transition
• Pseudogap metal induced by long-range Coulomb interactions
• Symmetry breaking and fermionic fractional Chern insulator in topologically trivial bands
• Long-Period Charge Correlations in Charge-Frustrated Molecular theta-(BEDT-TTF)2X
• Hidden Charge Order in an Iron Oxide Square-Lattice Compound
• Charge-Order on the Triangular Lattice: A Mean-Field Study for the Lattice $S=1/2$ Fermionic Gas
• 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
• Emergent lattices with geometrical frustration in doped extended Hubbard models
• Competing supersolids of Bose-Bose mixtures in a triangular lattice
• Thermal algebraic-decay charge liquid driven by competing short-range Coulomb repulsion
• Finite Temperature Properties of Geometrically Charge Frustrated Systems