Thermoelectric power of a degenerate 2D electron gas system under ionised impurity scattering
TL;DR: In this article, the authors calculated the thermoelectric power of a dynamically two-dimensional degenerate electron system in semiconductor inversion and accumulation layers, or other systems that exhibit twodimensional or quasi-two-dimensional behavior, under ionized impurity scattering.
Abstract: Electronic contributions to the thermoelectric power of a dynamically two-dimensional degenerate electron system in semiconductor inversion and accumulation layers, or other systems that exhibit two-dimensional or quasi-two-dimensional behaviour, are calculated under ionised impurity scattering. In the treatment the authors have also included a two-dimensional gas formed in semiconductor and semimetal films where the quantum size effect (QSE) is predominant. It has been found that the thermoelectric power decreases with the increase of interface carrier concentrations. Finally, results have been compared with recent experimental findings and the magnitude of the observed thermopower actually appears to agree quite well with the theoretical results of this paper.
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TL;DR: In this article, the Hall voltage of a two-dimensional electron gas, realized with a silicon metal-oxide-semiconductor field effect transistor, was measured and it was shown that the Hall resistance at particular, experimentally well-defined surface carrier concentrations has fixed values which depend only on the fine-structure constant and speed of light, and is insensitive to the geometry of the device.
Abstract: Measurements of the Hall voltage of a two-dimensional electron gas, realized with a silicon metal-oxide-semiconductor field-effect transistor, show that the Hall resistance at particular, experimentally well-defined surface carrier concentrations has fixed values which depend only on the fine-structure constant and speed of light, and is insensitive to the geometry of the device. Preliminary data are reported.
5,619 citations
TL;DR: The formation of a Wigner solid or charge-density-wave state with triangular symmetry is suggested as a possible explanation for the formation of the Hall plateau in magnetotransport of high-mobility, two-dimensional electrons as mentioned in this paper.
Abstract: A quantized Hall plateau of ${\ensuremath{\rho}}_{\mathrm{xy}}=\frac{3h}{{e}^{2}}$, accompanied by a minimum in ${\ensuremath{\rho}}_{\mathrm{xx}}$, was observed at $Tl5$ K in magnetotransport of high-mobility, two-dimensional electrons, when the lowest-energy, spin-polarized Landau level is $\frac{1}{3}$ filled. The formation of a Wigner solid or charge-density-wave state with triangular symmetry is suggested as a possible explanation.
3,528 citations
IBM1
TL;DR: In this article, the authors generalized the energy-level calculation to include arbitrary orientations of the constant energy ellipsoids in the bulk, the surface or interface, and an external magnetic field.
Abstract: The strong surface electric field associated with a semiconductor inversion layer quantizes the motion normal to the surface. The bulk energy bands split into electric sub-bands near the surface, each of which is a two-dimensional continuum associated with one of the quantized levels. We treat the electric quantum limit, in which only the lowest electric sub-band is occupied. Within the effective-mass approximation, we have generalized the energy-level calculation to include arbitrary orientations of (1) the constant-energy ellipsoids in the bulk, (2) the surface or interface, and (3) an external magnetic field. The potential associated with a charged center located an arbitrary distance from the surface is calculated, taking into account screening by carriers in the inversion layer. The bound states in the inversion layer due to attractive Coulomb centers are calculated for a model potential which assumes the inversion layer to have zero thickness. The Born approximation is compared with a phase-shift calculation of the scattering cross section, and is found to be reasonably good for the range of carrier concentrations encountered in InAs surfaces. The low-temperature mobility associated with screened Coulomb scattering by known charges at the surface and in the semiconductor depletion layer is calculated for InAs and for Si (100) surfaces in the Born approximation, using a potential that takes the inversion-layer charge distribution into account. The InAs results are in good agreement with experiment. In Si, but not in InAs, freeze-out of carriers into inversion-layer bound states is expected at low temperatures and low inversion-layer charge densities, and the predicted behavior is in qualitative agreement with experiment. An Appendix gives the phase-shift method for two-dimensional scattering and the exact cross section for scattering by an unscreened Coulomb potential.
1,468 citations
TL;DR: In this paper, a modulation-doping technique was used to spatially separate conduction electrons and their parent impurity atoms, thereby reducing the influence of ionized and neutral impurity scattering on the electron motion.
Abstract: GaAs‐AlxGa1−xAs superlattice structures in which electron mobilities exceed those of otherwise equivalent epitaxial GaAs as well as the Brooks‐Herring predictions near room temperature and at very low temperatures are reported. This new behavior is achieved via a modulation‐doping technique that spatially separates conduction electrons and their parent donor impurity atoms, thereby reducing the influence of ionized and neutral impurity scattering on the electron motion.
1,341 citations