Conductivity in a symmetry broken phase: Spinless fermions with $1/d$ corrections

Abstract

The dynamic conductivity $\sigma (\omega )$ of strongly correlated electrons in a symmetry broken phase is investigated in the present work. The model considered consists of spinless fermions with repulsive interaction on a simple cubic lattice. The investigated symmetry broken phase is the charge density wave (CDW) with wave vector $Q=(\pi ,\pi ,\pi {)}^{†}$ which occurs at half-filling. The calculations are based on the high dimensional approach, i.e. an expansion in the inverse dimension $1/d$ is used. The finite dimensionality is accounted for by the inclusion of linear terms in $1/d$ and the true finite dimensional DOS. Special care is paid to the setup of a conserving approximation in the sense of Baym/Kadanoff without inconsistencies. The resulting Bethe-Salpeter equation is solved for the dynamic conductivity in the non symmetry broken and in the symmetry broken phase (AB-CDW). The dc-conductivity is reduced drastically in the CDW. Yet it does not vanish in the limit $T\to 0$ due to a subtle cancellation of diverging mobility and vanishing DOS. In the dynamic conductivity $\sigma (\omega )$ the energy gap induced by the symmetry breaking is clearly discernible. In addition, the vertex corrections of order $1/d$ lead to an excitonic resonance lying within the gap.

23 pages, 19 figures included with psfig, Revtex; Physical Review B15, in press (October/November 1996) depending on the printer/screen driver, it might be necessary to comment out figures 3,4,5,10,11,12,19 and have them printed separately

References in corpus (6)

• Anomalous Normal-State Properties of High-T${}_c$ Superconductors -- Intrinsic Properties of Strongly Correlated Electron Systems?
• The Hubbard Model at Infinite Dimensions: Thermodynamic and Transport Properties
• Transport Properties of the Infinite Dimensional Hubbard Model
• Drude weight and dc-conductivity of correlated electrons
• Zero and Finite Temperature Phase Diagram of the Spinless Fermion Model in Infinite Dimensions
• Conductivity of interacting spinless fermion systems via the high dimensional approach

Cited by in corpus (6)

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• Transport functions for hypercubic and Bethe lattices
• Critical behavior of the extended Hubbard model with bond dimerization
• On the Analyticity of Solutions in the Dynamical Mean-Field Theory