Erratum to: Effect of Conductivity Type and Doping Level of Silicon Crystals on the Size of Formed Pore Channels during Anodic Etching in Hydrofluoric Acid Solutions

Technical Physics - An Erratum to this paper has been published: https://doi.org/10.1134/S106378422102016X     

Laser Effect in the Explosion of Porous Silicon

JETP Letters - In the explosive reaction of composites based on porous silicon with perchlorate oxidizers, a new effect has been discovered: the intensity accompanying the explosive reaction...     

Peak values of the longitudinal conductivity under integer quantum Hall effect conditions for sharp and smooth chaotic potentials

The problem of the peak values of the longitudinal conductivity under integer quantum Hall effect conditions is studied. The limiting cases of sharp and smooth chaotic potentials are considered. In the case of a sharp chaotic potential, the first longitudinal conductivity peak (δ _xx ⁽⁰⁾ ) obtained by the extrapolation of numerical data to an infinite sample size L→∞ is (0.55±0.03)e ²/h. In the case of a smooth chaotic potential, the peak values of the longitudinal conductivity are independent of the Landau level number and decrease as the chaotic-potential correlation length λ increases. The results obtained for sharp and smooth chaotic potentials agree with the reported experimental and numerically calculated data.     

Piezoelectric Properties of Porous Silicon

JETP Letters - The theoretical analysis and direct experiments with samples based on n- and p-type porous silicon demonstrate that porous silicon becomes a piezoelectric because of the reduction of...     

Energy Spectrum of Electrons of Deep Impurity Centers in Wide-Bandgap Mesoscopic Semiconductors

JETP Letters - The energy spectrum of deep impurity centers in wide-bandgap semiconductors (Eg > 2 eV) of mesoscopic sizes R ⪢ λD, where λD is the de Broglie wavelength, at...     

Terahertz emission from square wells in a longitudinal electric field

Terahertz emission accompanying heating of two-dimensional electrons by a strong electric field applied along size-quantized GaAs/AlGaAs layers is observed and investigated. The emission is due to indirect optical transitions of hot electrons in the bottom size-quantization band. The experimentally obtained emission spectra are compared with the spectra calculated taking into account scattering of electrons by optical phonons, impurities, and interfacial roughness and electron-electron scattering. Satisfactory agreement is obtained. The temperature of the hot electrons is determined from a comparison of the spectra. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 507–511 (10 April 1998)     

Effects of the reduction of the dimension of a system upon spin ordering in a degenerate electron gas

Collective effects of spin ordering in a quasi-one-dimensional degenerate electron gas are discussed. The total energy of the quasi-one-dimensional system, as well as the exchange contribution per particle, has been calculated by the Hartree-Fock method. It has been shown that spontaneous polarization can be observed in the system when a universal parameter related to the density of the particles satisfies the inequality r _s ≥ 0.476. A comparative analysis of one-, two-, and three-dimensional systems has been performed. A general expression has been obtained for the total energy per particle as a function of the degree of polarization and dimension of the system. According to this expression, the possibility of spontaneous polarization in the system is closely correlated with the dimension of the system.     

Density of states of a one-dimensional disordered photonic crystal

An analytic theory of the density of states in one-dimensional disordered photonic crystals is proposed. It is shown that the problem of the density of optical modes can be reduced in the small dielectric contrast approximation to solving a generalized Fokker-Planck equation for the distribution function of the logarithmic derivative of the electric field (the wave phase). The exact analytic solution and density-of-states asymptotics deep in the band gap of the photonic crystal and close to the band gap edge are derived. The results obtained agree well with the empirical relations derived earlier from numerical experiments.     

Impact sensitivity of energy systems based on nanoporous silicon and oxidant: influence of the hydrogen content and specific surface

The impact sensitivity of the energy systems based on nanoporous silicon, obtained by electrochemical etching of monocrystalline silicon wafers in an HF-containing electrolyte, and calcium perchlorate was studied using a modified Weller—Ventselberg technique (estimation of the impact sensitivity of initiating explosives). The impact sensitivity of these systems is shown to be determined by both the presence of hydrogen, which is stored on the porous silicon surface during the preparation of the latter, and also the influence of other factors, including the specific surface of porous silicon. The composition, amount of the generated gas, and gas evolution rate during nonisothermal and isothermal calcination of porous silicon in a temperature range of 60—120 °С were determined using methods of thermal gravimetry (TG), measurement of the gas volume, and mass spectrometry. The generated gas almost completely consists of hydrogen, and its content in the studied samples of porous silicon achieved ~3.8 wt.%. The calculated activation energy of the hydrogen evolution process in vacuo was 103.7±3.3 kJ mol^–1. The dependences of the impact sensitivity of the energy composition based on porous silicon and heat of combustion of porous silicon on oxygen on the hydrogen content were established. The impact sensitivity of the energy system decreases with a decrease in the hydrogen content in porous silicon and its specific surface.     

Heisenberg-Dirac-van Vleck vector model for a 1D antiferromagnetic chain of localized spins <Emphasis Type="Italic">S</Emphasis> = 1

Magnetic properties of anisotropic crystals with localized spins S = 1 are investigated; for these crystals, the Hamiltonian is derived in the Heisenberg-Dirac-van Vleck form, which includes biquadratic contributions apart from bilinear terms. The ground-state energy of the antiferromagnetic chain of spins S = 1 is calculated in the model of nearest neighbors, and the interaction constant is renormalized using the renorm group method in the case of coarsening of the system. The temperature criterion for the formation of long-range order in the system is obtained. The excitations of this chain in the linear approximation have a dispersion relation differing from that for antiferromagnets with spin S = 1/2 and are separated by an energy gap from the ground state. Allowance for nonlinear contribution leads to the formation of a solitary wave in the form of a dark-bright soliton.