Competition between charge and spin order in the $t-U-V$ extended Hubbard model on the triangular lattice

Abstract

Several new classes of compounds can be modeled in first approximation by electrons on the triangular lattice that interact through on-site repulsion $U$ as well as nearest-neighbor repulsion $V$. This extended Hubbard model on a triangular lattice has been studied mostly in the strong coupling limit for only a few types of instabilities. Using the extended two-particle self consistent approach (ETPSC), that is valid at weak to intermediate coupling, we present an unbiased study of the density and interaction dependent crossover diagram for spin and charge density wave instabilities of the normal state at arbitrary wave vector. When $U$ dominates over $V$ and electron filling is large, instabilities are chiefly in the spin sector and are controlled mostly by Fermi surface properties. Increasing $V$ eventually leads to charge instabilities. In the latter case, it is mostly the wave vector dependence of the vertex that determines the wave vector of the instability rather than Fermi surface properties. At small filling, non-trivial instabilities appear only beyond the weak coupling limit. There again, charge density wave instabilities are favored over a wide range of dopings by large $V$ at wave vectors corresponding to $\sqrt{(}3)\times \sqrt{(}3)$ superlattice in real space. Commensurate fillings do not play a special role for this instability. Increasing $U$ leads to competition with ferromagnetism. At negative values of $U$ or $V$, neglecting superconducting fluctuations, one finds that charge instabilities are favored. In general, the crossover diagram presents a rich variety of instabilities. We also show that thermal charge-density wave fluctuations in the renormalized classical regime can open a pseudogap in the single-particle spectral weight, just as spin or superconducting fluctuations.

References in corpus (24)

• Spin Liquid State in an Organic Mott Insulator with Triangular Lattice
• Spin entropy as the likely source of enhanced thermopower in $\rm\bf Na_xCo_2O_4
• Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)
• Non-perturbative many-body approach to the Hubbard model and single-particle pseudogap
• Superconductivity Phase Diagram of Na(x)CoO(2).1.3H(2)O
• An Electronic Model for $Co{O}_2$ layer based systems: Chiral RVB metal and Superconductivity
• Patterning of sodium ions and the control of electrons in sodium cobaltate
• Spin correlations in the electron-doped high-transition-temperature superconductor Nd{2-x}Ce{x}CuO{4+/-delta}
• Pseudogap and Spin Fluctuations in the Normal State of Electron-Doped Cuprates
• Thermodynamic and Transport Measurements on Superconducting Na_xCoO_2 + yH_2O Single Crystals Prepared by Electrochemical De-intercalation
• Observation of Bulk Superconductivity in NaxCoO2.yH2O and NaxCoO2.yD2O Powder and Single Crystals
• Possible effects of charge frustration in Na${}_x$CoO${}_2$: bandwidth suppression, charge orders and resurrected RVB superconductivity
• Electron correlation and Fermi surface topology of Na${}_x$CoO${}_2$
• Theory of spin and charge fluctuations in the Hubbard model
• Many-body Theory vs Simulations for the pseudogap in the Hubbard model
• Pairing fluctuations and pseudogaps in the attractive Hubbard model
• Dynamical mean field study of the Mott transition in the half-filled Hubbard model on a triangular lattice
• Study of the triangular lattice tV model near x=1/3
• Electronic texture of the thermoelectric oxide Na0.75CoO2
• Charge order and superconductivity in a two-dimensional triangular lattice at n=2/3
• Non-Perturbative Treatment of Charge and Spin Fluctuations in the Two-Dimensional Extended Hubbard Model: Extended Two-Particle Self-Consistent Approach
• Nearest-Neighbor Repulsion and Competing Charge and Spin Order in the Extended Hubbard Model
• The low-energy ARPES and heat capacity of Na${}_{0.3}$CoO${}_2$: A DMFT study
• Order and disorder in the triangular-lattice t-J-V model at 2/3 electron density

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• Nonlocal corrections to dynamical mean-field theory from the two-particle self-consistent method
• Considerable non-local electronic correlations in strongly doped Na${}_x$CoO${}_2$
• Charge-Order on the Triangular Lattice: A Mean-Field Study for the Lattice $S=1/2$ Fermionic Gas
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• Theory of carrier concentration-dependent electronic behavior in layered cobaltates
• Multiorbital kinetic effects on charge ordering of frustrated electrons on the triangular lattice
• Spin Hall conductivity in the Kane-Mele-Hubbard model at finite temperature
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