Quantitative Analysis of Valley–Orbit Coupling in Germanium Doped with Group-V Donors

Semiconductors - The wave functions of electrons localized at P, As, and Sb shallow donors in Ge are calculated in the envelope function approximation taking into account valley–orbit...     

Effect of Magnetic Co–CoO Particles on the Carrier Transport in Monolayer Graphene

Physics of the Solid State - Electrodeposition of cobalt on monolayer graphene synthesized by chemical vapor deposition produces Co–CoO/graphene composite structures, which is accompanied by...     

Effect of electric field on the ratio between the rashba and dresselhaus parameters in III–V heterostructures

The size-quantized energy subbands and envelope wave functions for [001] quantum wells based on zinc-blende III–V semiconductors are numerically calculated using the eight-band Kane model and finite-difference discretization scheme in coordinate space. The effect of the quantum-well band parameters and external electric field oriented along the structure growth direction on the ratio between the Rashba and Dresselhaus spin–orbit coupling parameters is studied. It is demonstrated that at certain electric-field values the spin–orbit coupling parameters in GaAs/InGaAs structures can be equal, which ensures the condition for forming stable spin helices. In addition, it is established that the spin–orbit coupling linear in wave vector in symmetric GaAs/InGaAs wells can disappear under certain well widths and barrier chemical compositions.     

Weak Error for Stable Driven Stochastic Differential Equations: Expansion of the Densities

Consider a multidimensional stochastic differential equation of the form X_t=x+ò₀^tb(X_s-) ds+ò₀^tf(X_s-) dZ_sX_{t}=x+\int_{0}^{t}b(X_{s-})\,ds+\int_{0}^{t}f(X_{s-})\,dZ_{s}, where (Z _s ) _s≥0 is a symmetric stable process. Under suitable assumptions on the coefficients, the unique strong solution of the above equation admits a density with respect to Lebesgue measure, and so does its Euler scheme. Using a parametrix approach, we derive an error expansion with respect to the time step for the difference of these densities.     

Asymptotic properties of some functions of nonparametric estimates of a density function

Let be a nonparametric estimate of a two-dimensional density f(x,y) constructed with the help of two-dimensional “window.” The main purpose of the paper is to study the asymptotic properties of the marginal moments estimates and differentiable functions , of these moments.     

Sup-norm convergence rates for Lévy density estimation

In this paper, we consider projection estimates for Lévy densities in high-frequency setup. We give a unified treatment for different sets of basis functions and focus on the asymptotic properties of the maximal deviation distribution for these estimates. Our results are based on the idea to reformulate the problems in terms of Gaussian processes of some special type and to further analyze these Gaussian processes. In particular, we construct a sequence of excursion sets, which guarantees the convergence of the deviation distribution to the Gumbel distribution. We show that the exact rates of convergence presented in previous articles on this topic are logarithmic and construct the sequence of accompanying laws, which approximate the deviation distribution with polynomial rate.     

Migration of excited charge carriers in arrays of phosphorus-doped silicon nanocrystals

The rate of tunnel migration of excited charge carriers (electrons and holes) in the array of silicon nanocrystals doped with phosphorus is calculated. It is shown that, starting from certain phosphorus concentrations dependent on the relation between the dimensions of the emitting and accepting nanocrystals, the rate of tunneling of electrons sharply decreases (by several orders of magnitude) and becomes lower than the rate of interband radiative recombination     

Local limit theorems for transition densities of Markov chains converging to diffusions

We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Local limit theorems for transition densities are proved. Received: 28 August 1998 / Revised version: 6 September 1999 / Published online: 14 June 2000