The Effect of Temperature and Coupling Strength on the Thermoelectric Power in the Small‐Polaron Hopping Regime

Triberis, G. P.

doi:10.1002/pssb.2221360143

Cited by 8 publications

(2 citation statements)

References 7 publications

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“…According to the mathematical analysis of the generalized molecular crystal model it is the condition hω 0 k B T [76] that determines the 'high' or the corresponding 'low' temperature regime [76,79]. This mathematical analysis leads to the evaluation of the intrinsic transition rate, which differs at high temperatures (multi-phonon-assisted hopping), compared with that at low temperatures (few-phonon-assisted hopping), and consequently results in different percolation conditions.…”

Section: Resultsmentioning

confidence: 99%

The effect of correlations on the non-ohmic behavior of the small-polaron hopping conductivity in 1D and 3D disordered systems

Dimakogianni

Triberis²

2010

J. Phys.: Condens. Matter

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According to percolation theory the investigation of charge transport in disordered systems is equivalent to the study of the possibility of the passage of the carriers through a random network of impedances which interconnect the different lattice sites. When the site energies are not the same, the energy of a site affects the incoming as well as the outgoing impedances connected to the given site and this gives rise to correlations between neighboring impedances. This new condition characterizes the transport process and imposes the evaluation of the average number of sites accessible by a bond from a given site for all possible configurations of sites that satisfy the percolation condition. The generalized molecular crystal model, appropriate for the study of small-polaron hopping transport in disordered systems, and the Kubo formula permit the evaluation of these impedances. Taking correlations into account, theoretical percolation considerations applicable to one-dimensional and three-dimensional disordered systems, lead to analytical expressions for the temperature and electric field dependence of the DC conductivity at high (multi-phonon-assisted hopping) and low (few-phonon-assisted hopping) temperatures. The theoretical analysis reveals the effect of correlations on the non-ohmic behavior of the small-polaron hopping conductivity and permits the evaluation of the maximum hopping distance. Quantitative estimates of this effect are presented comparing the theoretical results, including correlations with those ignoring them, previously reported, applying them to recent experimental data for a wide temperature range and from low up to moderate electric fields.

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Section: Resultsmentioning

confidence: 99%

The effect of correlations on the non-ohmic behavior of the small-polaron hopping conductivity in 1D and 3D disordered systems

Dimakogianni

Triberis²

2010

J. Phys.: Condens. Matter

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show abstract

“…According to the mathematical analysis of the generalized molecular crystal model it is the condition hω 0 k B T [53] that determines the 'high' or the corresponding 'low' temperature regime [53,65]. This mathematical analysis leads to the evaluation of the intrinsic transition rate, which differs at high temperatures (multi-phonon assisted hopping), compared with that at low temperatures (few-phonon assisted hopping), and consequently, results to different percolation conditions.…”

Section: Resultsmentioning

confidence: 99%

Field and temperature dependence of the small polaron hopping electrical conductivity in 1D disordered systems

Triberis¹,

Dimakogianni²

2009

J. Phys.: Condens. Matter

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We investigate the effect of the electric field and the temperature on the electrical conductivity of one-dimensional disordered systems due to phonon assisted hopping of small polarons. The microscopic transport mechanism is treated within the framework of the generalized molecular crystal model and the Kubo formula, while percolation theoretical arguments lead to analytical expressions for the macroscopic behavior of the electrical conductivity at high (multi-phonon assisted hopping) and low (few-phonon assisted hopping) temperatures under the influence of moderate electric fields. The theoretical results are successfully applied to recent experimental findings for a wide temperature range and from low up to moderate electric fields. Comparison is made with other theories.

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On the Importance of Correlations in the Study of the Conductivity Due to Small Polaron Hopping Motion in Amorphous Materials

Triberis

1990

Physica Status Solidi (b)

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According to percolation theory / I / , the study of the electron motion between localized states, which are randomly distributed in energy and position, in a disordered system, is equivalent to the study of the possibility of the passage of electric current through a network of impedances, Z.., which connect different lattice sites, i and j . Impedances of magnitude Zij *Zc, where Zc is the critical impedance, interconnecting small clusters of low impedances, form ak conductive cluster through the material.The inverse of the magnitude of impedances Z.. @ Zc, characterizes the A critical path of bonds can be constructed if the average number of bonds per site exceeds a certain critical value / 2 , 31. In this construction it is assumed that all sites are equivalent. When the site energies are not the same, the energy of a site affects the incoming as well as the outgoing 2'6, and this correlates neighboring Z's .Triberis and Friedman / 4 , 5 I , presented, using percolation theory, two methods for the calculation of the conductivity of the small polaron hopping regime in a disordered system. In the first they ignored correlations, while in the second they took correlations into account. Comparing these methods very useful conclusions were obtained and their results show how drastically correlations affect the temperature dependence of the conductivity. Using the generalized molecular crystal modes (GMCM) 14, 6, 71, they applied percolation theory to the high-temperature multiphonon-assisted small-polaron hopping regime in a disordered system (TF model I ) . They found / 4 / that the conductivity of the material varied as lncw [-(TAIT) ( 1) where T A = 8.5 N~12a3/2(kgNo) Here N is the concentration of sites, No the density of states, a-1 the spatial S ) Panepistimioupolis, G-15771 Zografou, Athens, Greece. ) Present address :

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The Effect of Temperature and Coupling Strength on the Thermoelectric Power in the Small‐Polaron Hopping Regime

Cited by 8 publications

References 7 publications

The effect of correlations on the non-ohmic behavior of the small-polaron hopping conductivity in 1D and 3D disordered systems

The effect of correlations on the non-ohmic behavior of the small-polaron hopping conductivity in 1D and 3D disordered systems

Field and temperature dependence of the small polaron hopping electrical conductivity in 1D disordered systems

On the Importance of Correlations in the Study of the Conductivity Due to Small Polaron Hopping Motion in Amorphous Materials

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