Density of states, relaxation dynamics, and hopping conductivity of disordered many-electron systems with long-range correlation

Schreiber, Michael; Tenelsen, K.; Vojta, Thomas

doi:10.1016/0022-2313(95)00202-2

Cited by 7 publications

(6 citation statements)

References 11 publications

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“…Later it has also been applied to simulate granular metals 10 and conducting polymers. 11,12 The model consists of a square or cubic lattice of linear size L with N = L d sites (in d dimensions) and lattice constant a. The sites can be occupied by KN (0 < K < 1) electrons.…”

Section: Modelmentioning

confidence: 99%

Monte Carlo simulations of the dynamical behavior of the Coulomb glass

1997

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We study the dynamical behavior of disordered many-particle systems with long-range Coulomb interactions by means of damage-spreading simulations. In this type of Monte-Carlo simulations one investigates the time evolution of the damage, i.e. the difference of the occupation numbers of two systems, subjected to the same thermal noise. We analyze the dependence of the damage on temperature and disorder strength. For zero disorder the spreading transition coincides with the equilibrium phase transition, whereas for finite disorder, we find evidence for a dynamical phase transition well below the transition temperature of the pure system.

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Section: Modelmentioning

confidence: 99%

Monte Carlo simulations of the dynamical behavior of the Coulomb glass

1997

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“…The theoretical investigations dedicated to PANI are also plentiful and cover almost all computational levels, i.e., molecular mechanics and dynamics [17] (doping mechanism, proton migration, temperature dependence of absorption, and conductivity), Monte Carlo [18,19] (interchain electronic transport in disordered systems), Hü ckel [20] (band structure, DOS), semi-empirical methods [21,22] (structure, UV/VIS spectra), as well as firstprinciple methods such as Hartree-Fock and DFT [23][24][25][26][27][28] (structure, infrared and Raman spectra). Some semi-empirical calculations are performed for the evaluation of torsion barriers and solvation effects on the UV/VIS spectra of PANI chains, accounted for by models including 2 to 4 solvent molecules [29,30].…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the structure and electronic spectra of fully protonated emeraldine oligomers

Zhekova

Tadjer

Ivanova

et al. 2006

Int J of Quantum Chemistry

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Polyaniline (PANI) is one of the most studied conducting polymers.Obtained in its conducting form (known as "emeraldine salt") by chemical or electrochemical oxidation of aniline in aqueous acidic medium, this polymer manifests an array of attractive properties. Nevertheless, these properties still need to be described at the molecular level. Intense theoretical investigations during the past few years aim at explaining the chain organization, conductivity mechanism, and other structural and spectral characteristics. Most studies adopt simplified models in which hydration effect is underestimated, since all simulations are performed either in vacuum or in the presence of a limited number of water molecules. The present computational study sheds light on the molecular organization of a number of model PANI hydrated clusters with different alignment and multiplicity, which can explain the experimentally recorded UV/VIS spectra. The influence of hydration and interaction with adjacent oligomers is estimated. Short-chain doubly protonated emeraldine oligomers are used as model systems. The calculations are performed at the semi-empirical (AM1) and/or molecular mechanics (AMBER96) level. Proper configurations of the clusters are selected using Monte Carlo simulations. Electron correlation (CIS) is accounted for upon evaluation of the absorption spectra of the clusters. The relative strength of the interchain coupling is estimated by simulation of PANI clusters consisting of two PANI tetramers in water. Comparison to experimental results is made.

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“…In heavily doped crystalline semiconductors, amorphous semiconductor-metal alloys, and granular metals, it plays an important role as a semiclassical model for systems of localized states. The dynamical behavior of the Coulomb glass has been studied by several groups: Schreiber et al, [4][5][6][7] as well as Pérez-Garrido et al, 8,9 determined numerically the transition probabilities between lowenergy many-particle states, and studied the eigenvalues of the transition probability matrix. Schreiber and co-workers directly diagonalized this matrix, whereas Pérez-Garrido and co-workers developed a renormalization method to eliminate the transitions with large rates, which considerably simplifies the diagonalization.…”

Section: Introductionmentioning

confidence: 99%

Nonergodic effects in the Coulomb glass: Specific heat

Díaz‐Sánchez¹,

Möbius²,

Ortuño³

et al. 2000

Phys. Rev. B

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We present a numerical method for the investigation of nonergodic effects in the Coulomb glass. An algorithm is developed to obtain an almost complete set of low-energy many-particle states. The dynamics of the sample is mapped to the graph formed by the relevant transitions between these states, that is, by transitions with rates larger than the inverse of the duration of the measurement. The formation of isolated clusters in the graph indicates nonergodicity. We analyze the connectivity of this graph in dependence on temperature, duration of measurement, degree of disorder, and dimensionality, studying how nonergodicity is reflected in the specific heat.

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Density of states, relaxation dynamics, and hopping conductivity of disordered many-electron systems with long-range correlation

Cited by 7 publications

References 11 publications

Monte Carlo simulations of the dynamical behavior of the Coulomb glass

Monte Carlo simulations of the dynamical behavior of the Coulomb glass

Theoretical study of the structure and electronic spectra of fully protonated emeraldine oligomers

Nonergodic effects in the Coulomb glass: Specific heat

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