Estimation of the solitary adatom charge

The Harrison method of bonding orbitals and the model of surface molecules are used to calculate the charge of a solitary adatom. The values of the charge are compared with those obtained earlier from the dependence of the work function of an adsorption system on the adatom concentration.     

Strain and temperature-dependent dielectric permittivity of cubic SrTiO3: Self-consistent phonon theory calculations

We examine the strain effect on the dielectric permittivity of cubic SrTiO₃ (STO) with Self-Consistent Phonon (SCP) theory calculations. Despite the soft mode frequency overestimation with this theory scheme and workflow, our calculations predict the correct tendency of TO1 with respect to temperature and strain. We found that a uniform tensile strain leads to softer TO1 modes. In addition, the TO1 frequency drops suddenly to zero at a specific temperature in the presence of a ferroelectric transition. The square linear relation between TO1 and temperature is used to estimate the Curie Temperature (T_C), and the STO dielectric permittivity calculated with the Lyddane-Sachs-Teller relation follows the Curie-Weiss (CW) law; which can also be used to determine another T_C value. Results from both approaches are in good agreement with each other and show that T_C increases significantly even when the applied tensile strain is only a few percent.     

Self-consistent calculations of alpha-decay energies

On the basis of the self-consistent theory of finite Fermi systems, the energies of alphadecay chains were calculated for several new superheavy nuclei discovered recently in experiments of the Dubna-Livermore Collaboration headed by Yu.Ts. Oganessian. The approach in question is implemented on the basis of the generalized method of the density functional proposed by Fayans and his coauthors. The version used here relies on the functional DF3-a proposed recently for describing a wide array of nuclear data, including data on superheavy nuclei. A detailed comparison of the results obtained on this basis with the predictions of different approaches, including the self-consistent Skyrme-Hartree-Fock method, the micro-macro method in the version developed by Sobiczewski and his coauthors, and the phenomenological method of Liran and his coauthors, is performed. The resulting alpha-decay energies are used to calculate respective lifetimes with the aid of the phenomenological Parkhomenko-Sobiczewski formula.     

Overcompleteness in the theory of chemisorption

The overcompleteness of the basis states when Anderson's Hamiltonian is applied to chemisorption is allowed for by using a pseudopotential to describe the atom-metal coupling. Some calculations for hydrogen on free-electron Al are reported.     

Self-consistent oscillations of the charge in a waveguide

Small oscillations of the charge in a rectangular waveguide are considered. The electromagnetic field generated by these oscillations and its effect on the charge are investigated. It is found that at a certain frequency there is a self-consistent regime of oscillations wherein the charge oscillates under the influence of its self-field in the absence of external forces. The combination of such a charge and the self-consistent alternating field has the property of a quasiparticle, which is named an electromagneton. Zh. Tekh. Fiz. 67, 120–121 (November 1997)     

On the theory of chemisorption

A solution of the Anderson model for chemisorption including correlation effects is presented. The solution becomes exact in three limiting cases (largeU, smallU i.e. Hartree-Fock and the so-called symmetric strong coupling limit) of the intra atomic Coulomb repulsionU and the hopping termV. Excellent agreement of our approximation with Schrieffer's exact numerical results for the binding energy of a small model system is found. Our results for the binding energy and the charge of the adsorbate show a significant improvement over the Hartree-Fock approximation. The single particle spectral density of the H-F approximation turns out to be even qualitatively wrong in the largeU strong coupling limit.     

Self-consistent calculations of magnetic properties in the lead region

Self-consistent calculations of magnetic properties in the lead region are presented. Finite-range and zero-range effective density-dependent forces have been used. The response of ²⁰⁸Pb to different magnetic probes has been examined. Neighbouring odd-A nulcei have been considered and renormalized values for different parts of the M1 operator are given.     

Self-consistent model of nanowire growth and crystal structure with regard to the adatom diffusion

A self-consistent model of growth and structure of semiconductor nanowires is proposed. The crystal phase of group III–V semiconductor nanowires is studied. The critical radius of the transition from the hexagonal wurtzite (WZ) structure to the cubic structure of zinc blende (ZB) type is calculated as a function of parameters of the system of materials and the gaseous medium supersaturation. The model presented here is applicable to both gas-phase and molecular beam epitaxies and allows one to calculate the probability of formation of the WZ and ZB phases under various deposition conditions.     

Self-consistent calculations of hypernuclear properties with the Skyrme interaction

An extension of the Skyrme-Hartree-Fock formalism is proposed for calculating Λ binding energies (B_Λ) in hypernuclei throughout the periodic table. The calculation includes the self-consistent nuclear polarization by the Λ hyperon. Realistic estimates for ground state B_Λ's are obtained with a simple effective ΛN force and are compared with a Λ-nucleus potential model. The Λ particle excitation spectra have also been calculated. They are discussed in the context of strangeness analog state formation and the emphasis is put on the symmetry between Λ and nuclear states.     

Self-consistent QRPA in the theory of nuclear structure

The conventional QRPA is extended to take into account the effect of the Pauli principle and the ground state correlations. The coupling between quasiparticle and phonons is found by minimizing the ground state expectation value of the auxiliary Hamiltonian. The model with pairing plus2-2 interaction is used.     

Self-consistent theory of Bose-condensed systems

In the theory of Bose-condensed systems, there exists the well known problem, the Hohenberg–Martin dilemma of conserving versus gapless approximations. This dilemma is analysed and it is shown that it arises because of the internal inconsistency of the standard grand ensemble, as applied to Bose systems with broken global gauge symmetry. A solution of the problem is proposed, based on the notion of representative statistical ensembles, taking into account all constraints imposed on the system. A general approach for constructing representative ensembles is formulated. Applying a representative ensemble to Bose-condensed systems results in a completely self-consistent theory, both conserving and gapless in any approximation.     

Self-consistent calculations of electric subbands in p-type GaAlAs-GaAs heterojunctions

The calculations in the Hartree-approximation indicate that only the heavy hole subband is occupied for carrier concentrations < 4×10¹²/cm² and that the spin degeneracy is lifted for finite wave vectors. Without magnetic field, two effective masses of 0.16 m_o and 0.61 m_o are deduced. A calculation of the Landau levels predicts a three-line cyclotron resonance absorption spectrum at high magnetic fields, which partially agrees with experimental data.