2003/01/07 by C. A. Perroni, V. Cataudella, G. De Filippis +3
Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.67.094302
published as Phys. Rev. B 67, 94302 (2003) · 8 figures. to appear on PRB
arxiv created 2003/01/07 · openalex publication_date 2003/03/06 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The phase diagram of the half-filled spinless Holstein model for electrons interacting with quantum phonons is derived in three dimensions extending at finite temperature T a variational approach introduced for the one-dimensional T=0 case. Employing the variational scheme, the spectral and optical properties of the system are evaluated in the different regimes that characterize the normal and ordered states. The effects of the charge ordering (CO) induce a transfer of spectral weight from low to high energies in the conductivity spectra, as the temperature decreases or the strength of the electron-phonon interaction increases. The inclusion of effects of lattice fluctuations is able to smooth the inverse square-root singularity expected for the case of the mean-field approach and determines a subgap tail absorption. Moreover, in the weak- to intermediate-coupling regime, a two-component structure is obtained within the CO phase at low frequency: the remnant Drude-like term and the incipient absorption band centered around the gap energy.