Diaplectic transformation of minerals: Vorotilov drill core, Puchezh-Katunki impact crater, Russia

The Vorotilov core was drilled in the central uplift of the Puchezh-Katunki astrobleme to a depth of 5.1 km. Impactites are revealed in the rocks of the core beginning from a depth of 366 m: suevites (66 m), allogenic breccias (112 m), and autogenic breccias (deeper than 544 m). These rocks are represented by shocked-metamorphic gneisses, schists, amphibolites of Archean age, and magmatic rocks (dolerites, olivines, and peridotites) that lie between them

Vortex Plasma in a Superconducting Film with Magnetic Dots

We consider a superconducting film, placed upon a magnetic dot array. Magnetic moments of the dots are normal to the film and randomly oriented. We determine how the concentration of the vortices in the film depends on the magnetic moment of a dot at low temperatures. The concentration of the vortices, bound to the dots, is proportional to the density of the dots and depends on the magnetization of a dot in a step-like way. The concentration of the unbound vortices oscillates about a value, proportional to the magnetic moment of the dots. The period of the oscillations is equal to the width of a step in the concentration of the bound vortices.Comment: RevTeX, 4 page

Electrical Manipulation of Nanomagnets

We demonstrate a possibility to manipulate the magnetic coupling between two nanomagnets with a help of ac electric field. In the scheme suggested the magnetic coupling in question is mediated by a magnetic particle contacting with both of the nanomagnets through the tunnel barriers. The electric field providing a successive suppression of the barriers leads to pumping of magnetization through the mediating particle. Time dependent dynamics of the particle magnetization allows to to switch between ferro- and antiferromagnetic couplings.Comment: 4 pages, 2 figure

Rectification in Luttinger liquids

We investigate the rectification of an ac bias in Luttinger liquids in the presence of an asymmetric potential (the ratchet effect). We show that strong repulsive electron interaction enhances the ratchet current in comparison with Fermi liquid systems, and the I-V curve is strongly asymmetric in the low-voltage regime even for a weak asymmetric potential. At higher voltages the ratchet current exhibits an oscillatory voltage dependence.Comment: 5 pages, Revte

Lattice dynamics and reduced thermal conductivity of filled skutterudites

The great reduction in thermal conductivity of skutterudites upon filling the ``void'' sites with Rare Earth (RE) ions is key to their favorable thermoelectric properties but remains to be understood. Using lattice dynamic models based on first principles calculations, we address the most popular microscopic mechanism, reduction via rattling ions. The model withstands inelastic neutron scattering and specific heat measurements, and refutes hypotheses of an anharmonic RE potential and of two distinct localized RE vibrations of disparate frequencies. It does indicate a strong hybridization between bare La vibrations and certain Sb-like phonon branches, suggesting anharmonic scattering by harmonic RE motions as an important mechanism for suppression of heat conductivity.Comment: modified version resubmitted to PRB. Results unchanged, text changed substantiall

Destruction of bulk ordering by surface randomness

We demonstrate that the arbitrarily weak quenched disorder on the surface of a system of continuous symmetry destroys long range order in the bulk, and, instead, quasi-long range order emerges. Correlation functions are calculated exactly for the two- and three-dimensional XY model with surface randomness via the functional renormalization group. Even at strong quenched disorder the three-dimensional XY model possesses topological order. We also determine roughness of a domain wall in the presence of surface disorder.Comment: 4 pages Revtex; Eq. (12) correcte

VUV photochemistry of the H2O center dot center dot center dot CO complex in noble-gas matrices : formation of the OH center dot center dot center dot CO complex and the HOCO radical

Vacuum ultraviolet (VUV, 130-170 nm) photochemistry of the H2O center dot center dot center dot CO complex is studied by matrix-isolation infrared spectroscopy. The H2O center dot center dot center dot CO complexes in Ne, Ar, Kr, and Xe matrices are generated by ultraviolet (UV, 193 and 250 nm) photolysis of formic acid (HCOOH). VUV photolysis of the H2O center dot center dot center dot CO complexes is found to lead to the formation of the OH center dot center dot center dot CO radical-molecule complexes and trans-HOCO radicals. It is shown that the matrix material, local matrix morphology, and possibly the H2O center dot center dot center dot CO complex geometry strongly affect the VUV photolysis pathways. The intrinsic reactivity of the matrix-isolated OH center dot center dot center dot CO complex resulting in the formation of trans-HOCO is directly demonstrated for the first time. This reaction occurs in Ar, Kr, and Xe matrices upon annealing above 25 K and may proceed over the barrier. The case of a Ne matrix is very special because the formation of trans-HOCO from the OH center dot center dot center dot CO complex is observed even at the lowest experimental temperature (4.5 K), which is in sharp contrast to the other matrices. It follows that quantum tunneling is probably involved in this process in the Ne matrix at such a low temperature. Infrared light also promotes this reaction in the Ne matrix at 4.5 K, which is not the case in the other matrices. The last findings show the effect of the environment on the tunneling and infrared-induced rates of this fundamental chemical reaction.Peer reviewe