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Fermi wavelength

Note finally that we fully neglected quantum effects. This is possible when a i/Xp/ (Xp is a Fermi wavelength). This criterion ensures that diffraction effects on the edges of the disks are not relevant at the scales of the order of /. In the opposite case, a -C y Xp . the diffraction should destroy the corridor effect , does suppressing the anomalous MR. The detailed analysis of quantum effects will be presented elsewhere. [Pg.74]

To conclude, the small momentum transfer contribution dominates Coulomb drag at almost all temperatures if the distance between the wires exceeds the Fermi wavelength, see Fig. 2. Drag by small momentum transfer is possible because electron dispersion relation is not linear, and therefore can not be accounted for in the conventional Tomonaga-Luttinger model. [Pg.126]

On the contrary, the Fourier transform of an image such as shown in Fig. 6 contains an internal calibration, because the distance separating the lattice spots in the Fourier transform is related to the lateral lattice parameter of Cu(lll). In this case one can determine with high precision the size of the surface Fermi wave vector, which turns out to be kp = 0.205 0.02 A, i.e. a Fermi wavelength of 30 3 A for Cu(lll), in nice agreement with... [Pg.14]

The Seitz radius rs is the radius of a sphere which on average contains one electron, so rs —> 0 in the high-density limit valence electrons typically have 1 bohr < r, < 6 bohr. The relative spin polarization ( vanishes for a spin-unpolarized system, and equals + 1 or -1 where all the electron spins are up or down, respectively. The inhomogeneity parameter s measures how fast the density varies on the scale of the local Fermi wavelength valence electrons typically have 0 < s < 3. Both rs and s diverge in the low-density tail of an atom or molecule. [Pg.6]

Moreover, the electron-phonon interactions in nanotubes are expected to be weak, due to the small area of the Fermi surface and the relatively large Fermi-wavelength, electronic back scattering from phonons is reduced compared with normal metals [149]. [Pg.425]

Field emission from carbon nanotubes may be more complex than implied by the analysis above since, in contrast to metal tips, the Fermi wavelengths are comparable to the tip size and consequently electronic states exist, which extend over the entire tip [152,168]. Emission is therefore not from individual atoms but from these tip states such that the emission is coherent. The field emission patterns from individual MWNTs in fact carry the signature of coherent emission from the tip states [168] (see Fig. 36). SWNTs have been imaged as well and the patterns correspond with calculated nanotube charge densities [152]. [Pg.430]

When the dimensions of the particles are shrinked from the bulk to a scale of the order of the Fermi wavelength of the electron, that is to a nanometer size, their behavior dominantly obeys the principles of quantum mechanics [6], One may therefore expect the emergence of new properties which may be entirely different from those of the bulk and sometimes are completely unexpected. It is believed that they are due to the so-called quantum size effect that modifies the electronic structure and increases the ratio... [Pg.219]

Fig. 6. Self-consistent surface charge density in the jellium model for K (solid line) and A1 (dashed line) (Lang and Kohn, 1 y70). Distance is measured in Fermi wavelengths from the positive background edge charge density is measured relative to the bulk density pa-... Fig. 6. Self-consistent surface charge density in the jellium model for K (solid line) and A1 (dashed line) (Lang and Kohn, 1 y70). Distance is measured in Fermi wavelengths from the positive background edge charge density is measured relative to the bulk density pa-...
Note that PW91 becomes more local as the density is reduced. The explanation is that, as n decreases from oo to 0, the hole density at the origin drops from -n/2 to -n, and, because it integrates to exactly -1, it becomes more localized, on the scale of the Fermi wavelength. [Pg.51]

Here we present a quantum mechanical model to calculate the experimentally observed interference patterns [3,5]. We include two-dimensional potential fluctuations, temperature effects as well as the back-scattering from the potential fluctuations. The latter effect alters the interference patterns strongly when the scattering center is located close (within the phase coherence length) to the sample boundaries. Constructive and deconstructive interference arise when the position of the scattering potential in the direction of the detector QPC is changed by 1/4 of the Fermi wavelength. [Pg.219]

By construction, LSD is exact for a uniform density, or more generally for a density that varies slowly over space [6]. More precisely, LSD should be valid when the length scale of the density variation is large in comparison with length scales set by the local density, such as the Fermi wavelength 27r/fcF or the screening length l/feg. This condition is rarely satisfied in real electronic systems, so we must look elsewhere to understand why LSD works. [Pg.33]

Alloy Lattice parameter" t/nm Fermi wavelength itp/ nm Amplitude A Phase factor rad... [Pg.170]

For a single quantum channel where the contact diameter is comparable to, or less than, the Fermi wavelength, Iq is given by... [Pg.184]

T= 18.5 K. Obviously, the oscillation period does not depend on the adatom type, but depends on the substrate, more precisely on the Fermi wavelength of the Shockley surface state. (From Ref [51].)... [Pg.154]


See other pages where Fermi wavelength is mentioned: [Pg.13]    [Pg.24]    [Pg.257]    [Pg.259]    [Pg.259]    [Pg.260]    [Pg.261]    [Pg.262]    [Pg.263]    [Pg.267]    [Pg.25]    [Pg.59]    [Pg.424]    [Pg.558]    [Pg.578]    [Pg.267]    [Pg.4]    [Pg.221]    [Pg.1441]    [Pg.301]    [Pg.305]    [Pg.729]    [Pg.250]    [Pg.123]    [Pg.1035]    [Pg.26]    [Pg.36]    [Pg.1035]    [Pg.184]    [Pg.105]    [Pg.148]    [Pg.153]    [Pg.167]    [Pg.168]   


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