Metal-to-Insulator Transition, Spin Gap Generation, and Charge Ordering in Geometrically Frustrated Electron Systems

Abstract

We investigate a (semi-)metal to insulator transition (MIT) realized in geometrically frustrated electron systems on the basis of the Hubbard model on a three-dimensional pyrochlore lattice and a two-dimensional checkerboard lattice. Using the renormalization group method and mean field analysis, we show that in the half-filling case, MIT occurs as a result of the interplay between geometrical frustration and electron correlation. In the insulating phase, which has a spin gap, the spin rotational symmetry is not broken, while charge ordering exists. The charge ordered state is stabilized so as to relax the geometrical frustration in the spin degrees of freedom. We also discuss the distortion of the lattice structure caused by the charge ordering. The results are successfully applied to the description of the MIT observed in the pyrochlore system $\mathrm{T}{\mathrm{l}}_2\mathrm{R}{\mathrm{u}}_2{\mathrm{O}}_7$.

12 pages, 10 figures

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Cited by in corpus (14)

• Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped Superconductivity
• Local Electron Correlations in a Two-dimensional Hubbard Model on the Penrose Lattice
• Quantum Disordered Ground States in Frustrated Antiferromagnets with Multiple Ring Exchange Interactions
• Low-energy properties of two-dimensional quantum triangular antiferromagnets: Non-perturbative renormalization group approach
• Magnetism in La2O3(Fe1-xMnx)2Se2 tuned by Fe/Mn ratio
• Mott-Hubbard transition and spin-liquid state on the pyrochlore lattice
• Systematic Analysis of Frustration Effects in Anisotropic Checkerboard Lattice Hubbard Model
• Unconventional Superconducting Symmetry in a Checkerboard Antiferromagnet
• Electronic properties of disordered corner-sharing tetrahedral lattices
• Strong ferromagnetic fluctuations in a doped checkerboard lattice
• Charge ordering in the spinels AlV${}_2$O${}_4$ and LiV${}_2$O${}_4$
• Magnetic Order and Mott Transition on the Checkerboard Lattice
• Orbital Mott transition in two dimensional Pyrochlore lattice
• Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping