Ground–state and dynamical properties of the 2D Holstein t–J model are examined by means of direct Lanczos diagonalization, using a truncation method of the phononic Hilbert space. The single– hole spectral function shows the formation of a narrow hole–polaron band as the electron–phonon coupling increases, where the polaronic band collapse is favoured by strong Coulomb correlations. In the two...

In system with strong electron-phonon (e-ph) interaction, the carriers lose mobility, ultimately acquiring polaronic character. A polaron is a state in which the phonon and electron degrees of freedom are strongly entangled, and the presence of an electron is associated to a finite lattice distortion, which in turn binds the electron leading to the so-called self-trapping effect. Polarons also ...

A single-particle spectral density is proposed for cuprates taking into account the bipolaron formation, realistic band structure, thermal fluctuations and disorder. Tunnelling and photoemission (PES) spectra are described, including the temperature independent gap observed both in the superconducting and normal states, the emission/injection asymmetry, the finite zero-bias conductance, the spe...

– We investigate metal-insulator transitions in the half-filled Holstein-Hubbard model as a function of the on-site electron-electron interaction U and the electron-phonon coupling g. We use several different numerical methods to calculate the phase diagram, the results of which are in excellent agreement. When the electron-electron interaction U is dominant the transition is to a Mott-insulato...

The synthesis and properties of a series of biand terthiophenes 3–8 substituted with meso-tetraphenylporphyrin (TPP) groups via an isolating oxaalkyl chain is described. Electrooxidative polymerization leads to the corresponding metal complexed porphyrin-functionalized polythiophenes P4–P8. The electrochemical and spectroscopic properties of the polymer films reveal the superimposition of the e...

We develop the nonadiabatic polaron theory of superconductivity of M x C 60 taking into account the polaron band narrowing and realistic electron-phonon and Coulomb interactions. We argue that the crossover from the BCS weak-coupling superconduc-tivity to the strong-coupling polaronic and bipolaronic superconductivity occurs at the BCS coupling constant λ ∼ 1 independent of the adiabatic ratio,...

At large electron-phonon coupling, the phonon of the Holstein-Hubbard model can be (generally) treated classically. Exact results can be obtained for this model at any band filling and any finite dimension where the Hubbard term with coefficient U is treated rigorously. The existence of chaotic bipolaronic states is proven when U is smaller than a certain value Uc and for an electron-phonon cou...

Fröhlich-Coulomb model of high-temperature superconductivity and charge segregation in the cuprates. Abstract. We introduce a generic Fröhlich-Coulomb model of the oxides, which also includes infinite on-site (Hubbard) repulsion, and describe a simple analytical method of solving the multi-polaron problem in complex lattice structures. Two particular lattices, a zigzag ladder and a perovskite l...

The electrochemical dedoping and redoping processes of a thin poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film immersed in an electrolyte are studied at different temperatures with time-resolved spectroelectrochemistry the visible near-infrared range. spectral signatures neutral, polaronic, bipolaronic states PEDOT resolved using multivariate curve resolution analysis. K...