Topic
Effective mass (solid-state physics)
About: Effective mass (solid-state physics) is a research topic. Over the lifetime, 12539 publications have been published within this topic receiving 295485 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, a model that describes grain-boundary-limited conduction in polycrystalline semiconductors, for thermally assisted ballistic as well as diffusive transport, both for degenerate and nondegenerate doping, is presented.
Abstract: We present a model that describes grain-boundary-limited conduction in polycrystalline semiconductors, for thermally assisted ballistic as well as diffusive transport, both for degenerate and nondegenerate doping. In addition to bulk parameters (the carrier effective mass and mean free path) the model contains grain boundary parameters (barrier height and width) and a coefficient of current nonuniformity. Temperature-dependent conductivity and Hall measurements on polycrystalline SnO2 thin films with different Sb concentrations are consistently interpreted.
71 citations
TL;DR: From a combination of optical reflectivity and electrical transport measurements, it is experimentally proved that the outstanding performance of IV-VI compounds with octahedral-like coordination is due to the anisotropy of the effective mass tensor of the relevant charge carriers.
Abstract: Thermoelectric materials provide a challenge for materials design, since they require optimization of apparently conflicting properties. The resulting complexity has favored trial-and-error approaches over the development of simple and predictive design rules. In this work, the thermoelectric performance of IV-VI chalcogenides on the tie line between GeSe and GeTe is investigated. From a combination of optical reflectivity and electrical transport measurements, it is experimentally proved that the outstanding performance of IV-VI compounds with octahedral-like coordination is due to the anisotropy of the effective mass tensor of the relevant charge carriers. Such an anisotropy enables the simultaneous realization of high Seebeck coefficients, due to a large density-of-states effective mass, and high electrical conductivity, caused by a small conductivity effective mass. This behavior is associated to a unique bonding mechanism by means of a tight-binding model, which relates band structure and bond energies; tuning the latter enables tailoring of the effective mass tensor. The model thus provides atomistic design rules for thermoelectric chalcogenides.
71 citations
TL;DR: In this article, the authors observed the quantum-confined band edge emission from ZnSe quantum dots and the size dependence of the energy states, spin-orbit interaction, and Stokes shift.
Abstract: We observed the quantum-confined band edge emission from ZnSe quantum dots and the size dependence of the energy states, spin-orbit interaction, and Stokes shift. The band edge emission occurs in the ultraviolet blue. The energy gap=Eg+C/dn where d is the diameter and n is 1.19±0.13 and 1.21±0.13 for the first and second electron-hole transitions, respectively. The separation between these transitions approaches the bulk spin-orbit splitting, while the Stokes shift decreases with particle size. Effective mass theories cannot explain these results. Trap emission is observed in some samples in the green and red, resulting from Se-related traps.
71 citations
TL;DR: In this paper, the generalized Skyrme effective force (GSEF) is parametrized by the fit to several properties of the normal and isospin-rich nuclei.
Abstract: We parametrize the recently proposed generalized Skyrme effective force (GSEF) containing extended density dependence. The parameters of the GSEF are determined by the fit to several properties of the normal and isospin-rich nuclei. We also include in our fit a realistic equation of state for the pure neutron matter up to high densities so that the resulting Skyrme parameters can be suitably used to model the neutron star with the 'canonical' mass ({approx}1.4M{sub {center_dot}}). For the appropriate comparison, we generate a parameter set for the standard Skyrme effective force (SSEF) using exactly the same set data as employed to determine the parameters of the GSEF. We find that the GSEF yields larger values for the neutron skin thickness which are closer to the recent predictions based on the isospin diffusion data. The Skyrme parameters so obtained are employed to compute the strength function for the isoscalar giant monopole, dipole, and quadrupole resonances. It is found that in the case of GSEF, because of the larger value of the nucleon effective mass, the values of centroid energies for the isoscalar giant resonances are in better agreement with the corresponding experimental data than those obtained using the SSEF. We also present resultsmore » for some of the key properties associated with the neutron star of canonical mass and for the one with the maximum mass.« less
71 citations
TL;DR: In this paper, the second derivative of the magnetoresistance of high purity samples of n-type InSb, InAs and GaAs over a wide range of temperatures was observed.
Abstract: Magnetophonon peaks are observed in the second derivative of the magnetoresistance of high purity samples of n-type InSb, InAs and GaAs over a wide range of temperatures. The temperature dependence of the band-edge effective mass in each material is deduced and compared with that predicted from the dilatational component of the change in band gap with temperature. In the case of InSb, the agreement is excellent but, with InAs and GaAs, the observed change is greater than that predicted although still less than that obtained by substitution of the change of optical energy gap with temperature.
71 citations