Fermi velocity

We now introduce patches to cover the Fermi surface, as shown in Fig. 2. The sizes of each patch are 2A in vertical direction to the Fermi surface and 2Aj in horizontal direction. The quarks in a patch are treated to carry a same Fermi velocity. 

We see that at the leading order in I //j, expansion, the energy is independent of the residual momentum, l , perpendicular to the Fermi velocity. In HDET, therefore, the perpendicular momentum labels the degeneracy and should satisfy a normalization condition... 

Abstract. We compute the velocity correlation function of electronic states close to the Fermi energy, in approximants of quasicrystals. As we show the long time value of this correlation function is small. This means a small Fermi velocity, in agreement with previous band structure studies. Furthermore the correlation function is negative on a large time interval which means a phenomenon of backscattering. As shown in previous studies the backscattering can explain unusual conduction properties, observed in these alloys, such as for example the increase of conductivity with disorder. 

We conclude this subsection with several remarks on the interpretation of the anisotropy of Hc2. The largest in-plane anisotropy reported by Metlushko et al. (1997) coincides with the direction of the nesting vector (0.55,0,0). Another manifestation of strong local anisotropy effects is provided by deviations from the 9 (angular) dependence due to anisotropic effective masses (Fermi velocities)... 

Another way to P takes into account the Fermi velocities of the up spin and down spin electrons as well. Since we use P as a phenomenogical fitting parameter, the detailed definition of P is not of concern here. 

Fig. 1. Schematic energy spectrum of ID electrons with dispersion asymmetry. The particles with energies close to the Fermi energy f have an almost linear dependence on momentum and are classified by their Fermi velocities (vif - subband 1, V2F -subband 2).

The multiband superconductivity shows up only in the clean limit , where the single electron mean free path for the interband impurity scattering satisfies the condition / > hvF/Aav where vF is the Fermi velocity and Aav is the average superconducting gap [24,28,30,35],... 

In figure 3 we compare the time evolution of various electronic observables the dipole signal along the axis joining the projectile to the cluster s center of mass, the number of escaping elect.vons Nesc(t), and ionization probabilities. Results are shown for a typical test case of a Ar8+ projectile on a Nay cluster. The projectile velocity is v = 50 ao/fs, about, twice the electronic Fermi velocity vf and impact parameter is b = 22. The... 

FIGURE 14 A section of the Fermi surface of LuNi2B2C showing a nesting feature characterized by the wave vector q (0.55,0,0), and contour plot of the magnitude of the Fermi velocity (in 106 m/s) in the (001) plane through the r point (from Yamauchi and Harima, 2005). 

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