Thermoelectric power of a narrow constriction in the adiabatic approximation

Hot electron energy relaxation via acoustic-phonon emission in GaAs/Ga1 xAlxAs multiple quantum wells: well-width dependence

“…At such low temperatures, the electron distribution is often degenerate and Pauli exclusion is important in limiting the allowed scattering. The power loss from a degenerate electron gas due to scattering by acoustic phonons has been calculated by many authors (see for instance [2,10,18,23,[38][39][40][41][42][43]) in two distinct temperature regimes: (i) the low-temperature (Bloch-Grüneisen) regime, where the phonon population diminishes, such that n(ω q ) 1, and the Pauli exclusion increasingly restricts the allowed scattering processes; and (ii) the hightemperature (equipartition) regime, where hω q /k B T 1, and hence the phonon distribution can be approximated by…”

“…In view of these observations, we conclude that the piezoelectric scattering rates in the 2D case are somewhat overestimated for the samples with well widths in the range 51 L z 78 Å and, hence, the theoretical calculations of the 2D polar interactions need to be reconsidered. If screening were to be included in the 2D theoretical calculations, the polar component of the interaction would be reduced significantly [39,41]. However, Bennet et al [52] have shown that inclusion of the effects of both static and dynamic screening on the electron-acoustic-phonon interactions in GaAs/Ga 1−x Al x As MQWs with a 2D carrier density of about 1.0 × 10 16 m −2 does not account for the experimental observations.…”

“…This is a consequence of the fact that, although equation ( 15) has the same electron-temperature dependence of power loss for both the 2D and 3D models in the intermediate-temperature regime, the magnitudes of the deformation-potential (C np ) and piezoelectric (C p ) interactions in the 2D case (equations ( 12) and ( 13)) are different from those in the 3D case (equations ( 17) and ( 18)). Therefore, it appears that the large scatter in the value for the acoustic deformation potential of GaAs/Ga 1−x Al x As heterostuctures reported in the literature (see for example [10,12,41,51]) is, at least in part, due to the actual theoretical model used in the analysis of the experimental power loss data.…”

Thermal conductance and the Peltier coefficient of carbon nanotubes

“…When the Fermi level crossing takes place, () and ⌸() are expected to exhibit, respectively, a step structure and a peak structure with a quantized maximum. 22,30,31 Doped carbon nanotubes are found to display richer quantized structures as the magnetic flux varies, which suggests that the experimental verification of the ballistic behavior may be easier after doping.…”

Looking for the maximum low-temperature conductivity in selectively doped double heterojunctions

“…In the theoretical studies it is usually assumed that there exists a specific sheet electron concentration (n) or a specific number of subbands in the well or envelope functions of a certain form or a quantum well of a specific shape, etc. These simplifying hypotheses have been commonly used in one way or another [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The mobility is expressed as a 'function' of n but this procedure is limited by the arbitrary way of changing n. Characteristically, even when n is kept constant, it has been shown by experimentally [20] that the change in the shape of the envelope function (by varying the gate voltage) will change µ by up to 56%.…”