Lateral-surface superlattices in systems with spin-orbit coupling: Quantum states and bloch oscillations in an electric field

The quantum states of a two-dimensional electron gas with spin-orbit coupling located in the periodic potential of a lateral-surface superlattice are studied. The spin-split energy bands and the distribution of spin projections in the Brillouin zone are constructed. Bloch oscillations accompanied by spin precession in superlattices with spin-orbit coupling located in a constant electric field are studied.     

Anomalous two-phonon absorption in diamond nanocrystals embedded in amorphous carbon

Observation of anomalously strong IR absorption are reported in the region of two-phonon diamond frequencies in amorphous hydrogenated carbon films grown by cosputtering graphite and copper in a plasma. Up to five structural elements of bands having frequencies close to or coinciding with the figures quoted in the literature for two-phonon absorption bands in bulk diamond were observed. This suggests the presence of diamond nanocrystals in the grown layers. Observation of two-phonon absorption in thin films is in itself remarkable because of the smallness of its coefficient in bulk diamond. An estimate of the absorption coefficient in the dominant band at 2140 cm^?1 yields about 200 cm^?1, which exceeds by more than an order of magnitude that for bulk diamond. This can be assigned to an anomalous enhancement of the two-phonon absorption coefficient due to phonon confinement in the small diamond particles nucleated in the amorphous carbon matrix. An estimate of these inclusions from the band width yields about 20 Å. The reasons for the catalytic activity of copper in diamond nucleation are analyzed.     

Quasistationary Approximation for the Stefan Problem

To justify the quasistationary approximation for the Stefan problem, the difference between the solution to the Hele-Show problem and the solution to the Stefan problem with small parameter ε at the time-derivative in the equation is considered. Bibliography: 7 titles. __________ Translated from Problemy Matematicheskogo Analiza, No. 31, 2005, pp. 167–178.     

On the mechanism of pressure increase with increasing porosity of the media compressed in conical and cylindrical targets

The effect of porosity on the solution of the problem on a shock wave entering a porous medium is studied. The dependence of the wave parameters appearing under shock compression of porous graphite, aluminum, and polytetrafluoroethylene in a steel target with a cavity in the shape of a truncated cone on the relative initial density is investigated. For a steel target with a cylindrical cavity filled with graphite, the effect of increasing the peak pressure on the symmetry axis in the case when the solid graphite is replaced with porous one is investigated.     

Birefringence of porous silicon

The paper reports the observation and studies of the birefringence in porous silicon samples obtained onto different crystallographic planes of silicon single crystals.     

An initial boundary-value problem with a noncoercive boundary condition in domains with edges

We consider an initial boundary-value problem for a second order parabolic equation in a domain with edges. We assume that on a part of the boundary the unknown function satisfies a boundary condition of the type (where is the external normal, φ is a given function). In the case of more than one space variable the existence results of the general theory of parabolic initial boundary-value problems do not apply to the problems with boundary conditions of this type. Unique solvability of the problem is established in weighted Sobolev spaces where the weight multipliers are certain powers of the distance to the edge. Bibliography: 17 titles. Dedicated to V. A. Solonikov on his sixtieth anniversary Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 213, 1994, pp. 206–223.     

Heat capacity of LiInTe2

The heat capacity of LiInTe₂ at constant pressure was measured with an adiabatic vacuum calorimeter in the temperature rangeT=7–300 K. The standard molar enthalpyH _m ⁰ —H _m ⁰ (0) and the standard molar entropyS ⁰ (T) were calculated. From a theoretical analysis, the contribution to the heat capacity due to the lattice anharmonicity was estimated.The increased effect of the lattice anharmonicity in LiInTe₂ is caused by specific properties of the Li-Te bond.

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Zusammenfassung Die Wärmekapazität von LiInTe₂ bei konstantem Druck wurde mit einem adiabatischen Vakuumkalorimeter im Temperaturbereich 7 T 300 K bestimmt. Die molare StandardenthalpieH _m ⁰ — H _m ⁰ (0) und die molare StandardentropieS ⁰ (T) wurden berechnet. Aus einer theoretischen Analys wurde der Anteil der Gitteranharmonizität an der Wärmekapazität abgeschätzt. Der erhöhte Einfluss der Gitteranharmonitität in LiInTe₂ wird durch spezifische Eigenschaften der Li-Te-Bindung verursacht

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7–300 LiInTe₂. H _M ⁰ -H _M ⁰ (0) S ⁰(T). . LiInTe₂ Li-.