Localized regime

All the above transitions are accompanied by changes in Seebeck coefficient, structural parameters, heat capacity and other characteristics. The V2O3 system has been explained in terms of a thermodynamic model which uses different free energy expressions for electrons in the itinerant and localized regimes (Honig Spalek, 1986). 

Fig. 1.29 Density of states N E) as a function of energy in a disordered material in the localized regime, showing the Coulomb gap of width A .

For we take the value given by the Kubo-Greenwood equation, namely equation (34) of Chapter 1. Mott (1970) showed that [Pg.158]

It is obvious that the role of randomness in the distribution of Mn acceptors and extrinsic defects, which is neglected in the model in question, will grow with approaching the localized regime. According to the two fluid model discussed previously, there is a... 

On physical grounds (see Section 10.3 and (15)) one should expect that low-energy polaritons in 2D organic microcavities would also be rendered strongly localized by disorder, as it would also follow from the general ideas of the theory of localization (39). Further work on microscopic models of two-dimensional polariton systems is required to quantify their localization regimes. 

Microwave measurements for PPy samples provide independent confirmation of the results reported at IR frequencies. Figure 15.46 compares (TdciT) with o-MwiT) for PPy(PF6) [29], PPy(TsO) [29], and PPy(S-PHE) [136]. The absolute values and the temperature dependence of cr in the dc and microwave frequency ranges for PPy(PF6) are nearly identical, in agreement with the Drude theory. The stronger temperature dependence of for PPy(TsO) and PPy(S-PHE) in comparison with cr wC T) is expected because the sample is in the localized regime [181]. 

The size of the copolymer varies in the weak localization regime as oc... 

For a Fermi glass, in which the states at Ep are Anderson localized, a photon of frequency co can activate the hopping near the Ep, resulting in finite o(w). In this case, Mott and Kaveh [1125,1157,1177] show that o(w) can be derived from the Kubo-Greenwood expression given in Eq. (4.10) in the localization regime... 

Although the thermopower, 5(7), of doped conducting polymers has been studied for many years, the evolution of 5(7) as a function of the extent of disorder is not yet fully understood. Usually, thermopower is not as sensitive to disorder as electrical conductivity, since the latter is strongly dependent on the scattering and hopping processes involved in charge transport in the disorder-induced localized regime. Kaiser [19] analyzed the... 

Sawicki, M., Dietl, T, Kossut, J., Igalson, J., Wojtowicz,T. and Plesiewicz, W. (1986) Influence of s-d exchange interaction on the conductivity of Cdi- Mn Sedn in the weakly localized regime. Physical Review Letters, 56, 508. 

If vG , respectively vGV, then we say that the system is in the localized regime, respectively the delocalized regime. 

If 5 > 1 (localized regime) then Q, N converges weakly to the measure concentrated on the constant function taking value zero. 

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