Showing papers on "Effective mass (solid-state physics) published in 1983"
TL;DR: In this article, the photochemical redox potential of one carrier, as a function of the size of the crystal, has been studied in the case of a small number of electrons.
Abstract: Large semiconductor crystals have intrinsic electronic properties dependent upon the bulk band structure. As the crystal becomes small, a new regime is entered in which the electronic properties (excited states, ionization potential, electron affinity) should be strongly dependent upon the electron and hole in a confined space. We address the possibility of a shift in the photochemical redox potential of one carrier, as a function of crystallite size. As a semiquantitative guide, one might expect a shift on the order of h2/8em*R2 due to the kinetic energy of localization in the small crystallite. We model the elementary quantum mechanics of a charged crystallite using (a) the effective mass approximation, (b) an electrostatic potential for dielectric polarization, and (c) penetration of the carrier outside the crystallite in a cases of small effective mass. Shifts of several tenths of an eV appear possible in crystallites of diameter 50 A. The carrier charge density reside near the crystallite surface if ...
1,479 citations
TL;DR: In this article, an effective mass equation governing the dynamics of electron motion using the Kohn-Luttinger representation and canonical transformations is derived, and it is shown that, as long as the variation in chemical composition may be treated as a perturbation, the effective masses become constant, position-independent quantities.
Abstract: A compound semiconductor possessing a slowly varying position-dependent chemical composition is considered. An effective-mass equation governing the dynamics of electron (or hole) motion using the Kohn-Luttinger representation and canonical transformations is derived. It is shown that, as long as the variation in chemical composition may be treated as a perturbation, the effective masses become constant, position-independent quantities. The effective-mass equation derived here is identical to the effective-mass equation derived previously by von Roos (1983), using a Wannier representation.
244 citations
195 citations
TL;DR: In this paper, the HgTe•CdTe superlattice was found to exhibit properties superior to those of the (Hg, Cd)Te alloy as an infrared detector material.
Abstract: The HgTe‐CdTe superlattice is found to exhibit properties superior to those of the (Hg, Cd)Te alloy as an infrared detector material. A calculation shows that the superlattice tunneling length is shorter than that of the alloy with the same band gap. For a given cutoff wavelength tolerance, we find that less fractional precision is needed in the superlattice control parameter (layer thicknesses) than in the alloy control parameter (composition). Also, p‐side diffusion currents are expected to be reduced due to the larger superlattice electron effective mass.
159 citations
TL;DR: In this paper, the cyclotron resonance absorption and emission experiments have been performed under hot-electron conditions and four different Landau-level transitions are observed, and different polaron theories are applied and their validity is discussed.
Abstract: Cyclotron resonance absorption and emission experiments have been performed under hot-electron conditions. Four different Landau-level transitions are observed. From the splitting of the cyclotron-resonance lines, polaron effects are determined. Different polaron theories are applied and their validity is discussed. An accurate treatment of polaron effects is found to be necessary for the determination of the band-edge effective mass, which is determined to be ${m}_{0}^{*}=0.0650m$.
107 citations
TL;DR: In this article, the effective mass of an electron in a GaAs heterostructure is calculated in the presence of electron-LO-phonon interaction within leading-order perturbation theory.
Abstract: The effective mass of an electron in a GaAs heterostructure is calculated in the presence of electron---LO-phonon interaction within leading-order perturbation theory. In the purely two-dimensional limit and without any screening effect, the polaron mass correction is found to be enhanced by almost a factor of 3 over the three-dimensional Fr\"ohlich result. Inclusion of screening and the subband wave-function effects decreases the mass correction appreciably, and excellent agreement with recent experimental results reporting negligible polaronic effect in GaAs heterostructure is obtained.
92 citations
TL;DR: In this article, Monte Carlo evidence was presented that the effective mass of the gluon scales correctly in the weak coupling regime and hence is non-zero and finite in the continuum limit.
84 citations
TL;DR: In this article, a large volume-high pressure technique at high temperature was used to obtain p-type single crystals of black phosphorus and the Hall mobility reached 5×10 4 cm 2 v·sec around 20K.
Abstract: Large single crystals of black phosphorus have been prepared by a large volume-high pressure technique at high temperature. Using the crystals, we have measured temperature dependences of the electrical conductivity and the Hall coefficient, the FIR cyclotron resonance absorption and the reflectance for synchrotron radiation. All samples obtained are p-type and the Hall mobility reaches 5×10 4 cm 2 v·sec around 20K. The anisotropies of the effective mass, the Hall mobility and the SOR reflectance along the three crystal directions, a, b, and c, have been observed.
77 citations
TL;DR: In this article, two nonlinear optical processes in superlattices are studied, one involving free carrier absorption and the other involving direct inter-subband absorption, which have picosecond relaxation times and nonlinearities up to four orders of magnitude larger than the nonlinear refractive effects in bulk crystals.
Abstract: Two nonlinear optical processes in superlattices are studied. The first involves free‐carrier absorption and the second involves direct intersubband absorption. The optical field modulates the energy‐dependent effective mass or the distribution of electrons among the subbands, giving rise to nonlinear refraction. These processes have picosecond relaxation times and nonlinearities up to four orders of magnitude larger than the nonlinear refractive effects in bulk crystals with comparable relaxation times.
69 citations
TL;DR: In this paper, the authors studied the electrical conductivity in single crystal rutile (TiO2) between 6 and 40 K by means of electrical resistance and Hall effect measurements.
Abstract: Electrical conductivity mechanisms in single crystal rutile (TiO2) between 6 and 40 K have been studied in Nb‐doped and Nb+H‐doped material by means of electrical resistance and Hall effect measurements. In this range, three scattering mechanisms were found to be important: neutral and ionized impurities and acoustic phonons. In the region from approximately 12 to 25 K the electrical conductivity was found to be strictly exponential in 1/T, indicating acoustic phonon limited scattering, and yielding the donor trapping energies for Nb and H (20.0±0.1 and 4.4±0.1 meV, respectively). With the acoustic phonon limited mobility written as μ=μ0/T3/2, μ0 was found to be (1.2±0.1)×104 and (3.9±0.4)×10−4 cm2(K)3/2/V s in the ‘‘a’’ and ‘‘c’’ directions, respectively. Although qualitative agreement with existing theories on neutral and ionized impurity scattering is obtained, quantitative agreement requires an improved theory taking anisotropy into account. It was also found that the ratio of ‘‘c’’ to ‘‘a’’ mobility ...
59 citations
TL;DR: In this paper, a new analysis has been developed to determine the layer strain as well as the composition of thick layers (∼ 300 A) from x-ray diffraction, which is in agreement with the previous work of Matthews and Blakeslee.
Abstract: The technique of metal organic chemical vapor deposi-tion has been used to prepare strained-layer superlattices in the GaAs + GaP system. The superlattices consist of alternating layers of GaP and GaAsxP1−x for x = 0.2 to 1.0, which vary in thickness from 30 to 400 A. The layers were grown by the decomposition of trlmethylgallium and various mixtures of ASH3 and PH3 in H2 at 800δC. The thickness and uniformity of the layers were determined by optical and transmission electron microscopy and x-ray diffraction. The composition of the layers was determined from x-ray diffraction. A new analysis has been developed to determine the layer strain as well as the composition of thick layers (∼ 300 A). Transmission electron microscopy has been used to yield direct evidence that strained-layer superlattices can be used to remove the misfit dislocations generated during the epitaxial growth of a GaAsxP1-x alloy on a lattice mismatched GaP substrate. These results are in agreement with the previous work of Matthews and Blakeslee. Optical absorption, photocurrent spectroscopy and photoluminescence have been used to deter-mine the band gap energy as well as the energies for other optical transitions. The values are in excellent agreement with the values predicted by tight binding and effective mass calculations.
TL;DR: In this article, the double donor character of a Si = 0 interstitial molecule is investigated and the experimental results can be explained qualitatively by the Si =0 interstitial molecules which can form donor complexes first with intersitial oxygen and then with increasingly bigger neutral Si.
Abstract: Spectroscopic experiments (EPR and IR) on the 450° C thermal donors (TD) in oxygen rich silicon confirm that they are double donors with an effective mass character and a ladder of ionization energies. Nine distinct centres are identified. The experimental results can be explained qualitatively by the double donor character of a Si = 0 interstitial molecule which can form donor complexes first with intersitial oxygen and then with increasingly bigger neutral Si.0 complexes.
TL;DR: In this article, a Skyrme functional is designed for calculations of nuclear masses and density distributions in a constrained time invariant Hartree-Fock + BCS model, with an effective mass equal to the nucleon mass.
TL;DR: In this article, the origin of differences found in recent microscopic calculations of the energy dependence of the effective mass in 208 Pb was investigated in the framework of various schematic models, showing the importance of shell effects and illustrate possible consequences of the use of a truncated configuration space in microscopic calculations.
TL;DR: In this paper, the authors derived the index of refraction n as a function of frequency and mole fraction x for the ternary compound Hg1−xCdxTe in terms of known experimental parameters and compared with recent experimental results.
Abstract: The index of refraction n is calculated as a function of frequency and mole fraction x for the ternary compound Hg1−xCdxTe in terms of known experimental parameters and compared with recent experimental results. The theoretical result for n is obtained from a quantum mechanical calculation of the dielectric constant of a compound semiconductor, which has been successfully applied to a number of III–V and II–VI binary, ternary, and quaternary compounds for which experimental data are available. The refractive index is calculated in terms of basic material parameters only, with no adjustable constants. These material parameters consist of band‐gap energy, effective electron mass, and effective heavy hole mass at the band edge, the lattice constant, the spin‐orbit splitting energy, and the carrier concentration for n‐type of p‐type materials. If these parameters are known as functions of mole fraction x and temperature, the refractive index is completely determined as a function of frequency below the fundamental absorption edge. The change in refractive index with increasing temperature depends mainly on the change in band‐gap energy with temperature and is expected to be positive for x>0.529 and negative for x<0.529 for Hg1−xCdxTe . A negative change in the refractive index at the absorption edge proportional to I1/3, where I is the incident radiation intensity, is predicted on passing radiation through a crystal if the change in carrier concentration of the initially unoccupied conduction band is assumed proportional to I.
TL;DR: In this paper, a tight-binding band-structure model of silicon superlattices is formulated and used to study systems of potential applied interest, including periodic layered Si-Si(1-x)Ge(x) heterostructures.
Abstract: A realistic tight-binding band-structure model of silicon superlattices is formulated and used to study systems of potential applied interest, including periodic layered Si-Si(1-x)Ge(x) heterostructures. The results suggest a possible new mechanism for achieving enhanced transverse carrier mobility in such structures: reduced transverse conductivity effective masses associated with the superlattice band structure. For electrons in 100-line-oriented superlattices, a reduced conductivity mass arises intrinsically from the lower symmetry of the superlattice and its unique effect on the indirect bulk silicon band gap. An order of magnitude estimate of the range of mobility enhancement expected from this mechanism appears to be consistent with preliminary experimental results on Si-Si(1-x)Ge(x) superlattices.
TL;DR: In this article, the influence of momentum and frequency dependence of the nuclear mean field Σ on the level density parameter a is studied, and it is found that the magnitude of ac is significant due to the very nature of the surface.
TL;DR: In this article, a local effective mass of quasiparticles in the nucleus is introduced to enhance high-momentum components in the ground-state wave function of nuclei, which allows for a simultaneous description of average single-particle dynamics close to the Fermi surface as well as features observed far away.
TL;DR: In this article, a sample of non-spectator events in the dp→(pn) p break-up reaction at 3.3 GeV/c deuteron momentum is studied using films from 1 m hydrogen bubble chamber.
TL;DR: In this paper, the real part of the refractive index near the fundamental absorption edge is given, which is based on a quantum mechanical calculation of the complex dielectric constant using the quantum density matrix method.
Abstract: A calculation of the real part of the refractive index near the fundamental absorption edge is given, which is based on a quantum mechanical calculation of the complex dielectric constant using the quantum density matrix method. An analytical expression is obtained in terms of experimentally known quantities for a given semiconductor and compared with available experimental data. The band structure of the Kane theory, which applies to direct gap III-V and II-VI compounds, is assumed. The expression obtained is a function of the band-gap energy, the effective electron and heavy hole masses at the bandedge, the spin orbit splitting energy, the carrier concentration for n-type or p-type materials, the temperature, and the frequency of the incident radiation. The temperature dependence occurs through the dependence of the bandgap energy and the effective mass on temperature for degenerate n-type or p-type materials, and there is an additional temperature-dependent factor for nondegenerate materials. The expression also involves the value of n at the absorption edge which is not accessible to measurement. However, an equation for n at the absorption edge can be found in terms of experimentally obtainable values of n near the absorption edge and solved to give the desired quantity. This can then be used to predict the refractive index to a high degree of accuracy over the entire frequency spectrum up to the bandedge. Within limits of the above statement regarding n at the absorption edge, there are no adjustable parameters involved, and this constitutes a significant improvement over previous theories of the refractive index of a semiconductor. In particular, the theory predicts the dispersion near the fundamental absorption edge which has been observed experimentally for a number of III-V and II-VI compounds and enables its precise calculations as a function of frequency. This fact is expected to be of considerable importance in technological applications involving integrated optics. Theory is compared with experimental results for a number of III-V and II-VI compounds.
TL;DR: In this article, an exact calculation was made for the temperature dependent density of states effective mass in p-type silicon for the non-degenerate regime and included the full nonspherical nonparabolic nature of the valence band structure.
Abstract: Previously, an exact calculation was made for the temperature dependent density of states effective mass in p‐type silicon. This calculation was made for the nondegenerate regime and included the full nonspherical‐nonparabolic nature of the valence band structure. For those researchers interested in using this mass for the analysis of their transport data we offer a polynomial fitted expression. The values generated are within 1% of the theoretical values.
IBM1
TL;DR: In this article, the effects of edge scattering in narrow inversion layer channels is considered and the effects on energy levels are discussed briefly and the scattering effects are discussed in more detail, including the consequences of a change in effective mass across a heterojunction interface.
TL;DR: In this paper, a general formula for the effective (electrical or thermal) conductivity of a porous insulator filled with a conductor is obtained, which depends on an induced-mass factor which arises by treating of the conducting material as an inviscid fluid.
Abstract: By combining of identities relating effective conductivity to tortuosity and tortuosity to induced mass, a general formula for the effective (electrical or thermal) conductivity of a porous insulator filled with a conductor is obtained. This formula depends on an induced-mass factor which arises by treating of the conducting material as an inviscid fluid. This induced-mass factor can be estimated with the use of an effective-medium theory. For random arrays of equal spheres, the estimates of conductivity obtained with the use of this fluid analogy are in good agreement with recent exact values derived for periodic arrays of insulating spheres to closest packing.
TL;DR: In this paper, a simple semi-empirical equation for the electron drift velocity in silicon as a function of electric field and temperature is derived from elementary physical assumptions, namely the low field mobility, effective mass, and optical phonon energy.
Abstract: A simple semi-empirical equation for the electron drift velocity in silicon as a function of electric field and temperature is derived from elementary physical assumptions. The parameters in this equation, namely the low field mobility, effective mass, and optical phonon energy, are well defined physical quantities, Excellent agreement with the empirical Scharfetter-Gummel equation is obtained. The temperature dependence of the saturation velocity and the warm electron coefficient β are also well described. A field dependent mobility scaling factor is derived to account for the steeper rise of the velocity-field profile in doped silicon which results from decreased coulombic scattering of hot carriers. The longitudinal electron diffusion is also crudely predicted.
TL;DR: In this article, a nonlinear relativistic mean field theory was proposed to study the nuclear surface properties, and the strength of the required parameters is determined from the binding energy and density of nuclear matter and the effective nucleon mass.
Abstract: The temperature dependence of the carrier concentration of Hg1−xCdx Te at elevated temperatures is used to determine its band parameters near the bandedge. The electron concentration is calculated by using the Kane model (k⋅p method), and is fit to observed values derived from measurements of the Hall coefficient in the near‐intrinsic region. This procedure results in expressions for the following parameters: the band‐gap Eg and its dependence on temperature and composition; Kane’s interband‐coupling matrix element and the heavy‐hole effective mass ratio. Modified values of the intrinsic carrier concentration are calculated using these parameters.
TL;DR: In this paper, it was shown that the gravitationally effective mass is exactly equal to the mass of the string, in contrast to the case of static string which produces no gravitational field.
TL;DR: In this article, an induced interaction model for the fully polarized phase of liquid 3 He is presented and some properties of this system are discussed and predictions made, and the effective mass, m ∗ m, is found to drop dramatically to ≈ 0.8, giving rise to interesting effects.
TL;DR: In this article, an analytical expression for the real part of the refractive index n near the fundamental absorption edge is given in terms of experimentally known quantities for a given semiconductor.
Abstract: An analytical expression for the real part of the refractive index n near the fundamental absorption edge is given in terms of experimentally known quantities for a given semiconductor. It is derived from a quantum mechanical calculation of the complex dielectric constant which assumes the band structure of the Kane theory. The expression obtained is a function of the band‐gap energy, the effective electron and heavy hole masses at the band edge, the spin orbit splitting energy, the carrier concentration for n‐ or p‐type materials, the temperature, and the frequency of the incident radiation. Also involved is the value of n at the fundamental absorption edge, which is not accessible to measurement. However, an equation for n at the absorption edge can be found in terms of experimentally obtainable values of n near the absorption edge and solved to give the desired quantity. The refractive index can then be predicted to a high degree of accuracy over the entire frequency spectrum up to the band edge. In pa...
TL;DR: In this paper, the optical absorption due to direct intersubband transitions and including the broadening effects has been calculated by using an electric dipole approximation for a quasi-one-dimensional semiconducting thin wire.
Abstract: The optical absorption due to direct intersubband transitions and including the broadening effects has been calculated by using an electric dipole approximation for a quasi‐one‐dimensional semiconducting thin wire. Effective mass approximation is adopted to determine the eigen functions and energies of the conduction electrons in Schrodinger equation by assuming a two‐dimensional infinite potential well. When the electromagnetic wave is polarized in a z direction which possesses a size‐quantization effect in the thin wire, the selection rule requires that the sum of the quantum numbers of the initial state and finial state must be odd integers. ac and dc conductivities, and the absorption line shapes due to collisions are discussed.