Density of stales

Here and below we assume e to be positive, which is sufficient in view of the symmetry of p(e) for the Hamiltonian Eq. (3.10). For g<2 the density of stales has a pseudogap (the Peierls gap filled with disorder-induced states). For g>2 the pseudogap disappears and the density of states becomes divergent at c=0. 

Figure 3-5. Disorder-averaged density of stales />(< ) in the FGM for three values ol Hie dimensionless disorder strength g=0, i.c., no disorder (eurve a), g=0.25 (curve b), g=4 (curve e). The (tec electron density of stales was set to unity.

It must be noted that the prerequisite to see distinct peaks in a TSC experiment is a sleep onset of the density of stales at the band edges. This is fully fulfilled... 

Another effect of the electron-phonon interaction is a shift in the velocity of the electrons at the Fermi surface, in some ways analogous to the polaron effect in ionic crystals. Because of the wake of lattice distortion that accompanies the electron, its velocity is reduced, as it turns out, by a factor (I -t A) E (I- or a discussion of this effect, and references, sec Quinn, 1960, p. 58, oi Harrison, 1970, p. 418ff.) The reduction in velocity corresponds to a decrease in dE/dk at the Fermi surface and, therefore, to an increase in the density of stales by the same factor. We noted in Chapter 15 that the electronic specific heal is proportional to the density of states, so we may expect an enhancement of the experimental... 

Let us return to the d stales which, for each transition metal, at a given / o, are characterized by an average energy Ej with respect to the minimum of the free-electron band and a width Wj. The corresponding model density of stales is illustrated in Fig. 20-8,b. Given Wj and E, we can easily compute the value ofE,. that is consistent with the number of electrons present. 

As can be readily seen, the density of stales at any given energy is inversely proportional to the slope of the energy function at that energy. 

Figure 2.78a. The impurity-induced density of stales (DOS) for hydrogen in jellium at r, = 2.07, corresponding to Al. The local induced DOS An describes states within a radius of 10 au around the proton. Also shown are the s-components of this quntity, Anf, and of the total DOS. An i l.

NOcrocanonical IVaa lioii-slale Theory and Mfinimnai Density of Stales.—Several authors have discussed the application of microcanonical transition-state theory, together with die use of the ariterion of minimum state density. " This can be dealt with concisely in terms of the adiabatic diannel model (the basic ideas of the following discussion have been givm also by Eliason and Hirschfelder).< ... 

Fig. 1. Schematic spectrum of the density of stales of (a) the impurity Kondo case and (b) the Kondo lattice, including split-off bands at E and + [/ and the many-body resonance of width T. The scale Tr is expanded for clarity. (After Martin 1982.)...

EXELFS Extended Electron Energy Loss Fine Structure Thin films Electrons (100-400 keV) Electrons energies 0-30 eV above edge <200 nm 1-100 nm Density of stales of valence eleclrons (above Fermi level) 27,32... 

---