Electron-electron interactions in the 2D electron system

In this paper, we report studies of the electron-electron interaction effects in 2D electron systems. The interaction manifests in renormalization of the effective spin susceptibility, effective mass, g^∗-factor, conductivity etc. By applying in-plane magnetic field, we tuned the effective interaction between the electrons and compared with theory the temperature dependence of the conductivity. We find a good agreement with interaction corrections calculated within the Fermi liquid theory. To address the question on the origin of the metal-insulator transition (MIT) in 2D, we explored transport and magnetotransport properties in the vicinity of the MIT and compared our data with solutions of two equations of the renormalization group (RG) theory, which describes temperature evolutions of the resistivity and interaction parameters for 2D electron system. We found a good agreement between the ρ(T,B_∥) data and the RG-theory in a wide range of the in-plane fields. These results support the Fermi liquid type origin of the metallic state and the interpretation of the observed 2D MIT as the true quantum phase transition.     

Experimental and theoretical study of the transannular intramolecular interaction and cage effect in the atrane framework of boratrane and 1-methylsilatrane

On the basis of the high-resolution single-crystal X-ray diffraction data and theoretical B3LYP/6-311+G(d) and B3LYP/cc-pVDZ calculations, the electron density distribution in boratrane and 1-methylsilatrane has been investigated. The B-N bond in the boratrane molecule was found to correspond to the "shared" (covalent) interatomic interaction in terms of Bader's "atoms in molecules" (AIM) theory. On the contrary, the Si...N bond in 1-methylsilatrane and B-N bond in a series of some acyclic donor-acceptor boron complexes and other boratrane derivatives correspond to interaction of an "intermediate" type. Such character of the B-N bond is caused by an influence of the atrane "cage effect". The influence of this effect results in deformation of the boron atom and displacement of the bond critical point (3,-1) to the region of the electron lone pair of the nitrogen atom. This changes the type of the interatomic interaction in comparison to other compounds investigated and explains high hydrolytic stability of boratrane as well as silatranes and germatranes.     

Optical spectroscopy and electronic structure of the GdCu x compounds (x = 1, 2, 5)

Physics of the Solid State - Optical properties of the GdCu, GdCu2, and GdCu5 compounds with various crystal lattices have been investigated using ellipsometry in a spectral range of 0.22–16...     

Effect of copper and cobalt impurities on the electronic structure and optical spectra of the intermetallic compound PrNi5

The electronic structure and optical properties of the intermetallic compound PrNi₅ and their evolution during the substitution of copper or cobalt atoms for nickel atoms have been investigated. The band spectra of the studied compounds have been calculated in the local spin density approximation corrected to account for strong electron-electron interactions in the 4f shell of the rare-earth ion (LSDA + U method). The dispersion relations of the optical conductivity in the interband light absorption region have been interpreted using the results of calculations of the electron density of states.     

Effect of a Travelling Magnetic Field on the Parameters of Tellurium-Doped Gallium Arsenide Single Crystals Grown by the Czochralski Method

Crystallography Reports - The effect of a traveling magnetic field on the parameters of Te-doped GaAs single crystals in the carrier density range of 5 × 1017–2 ×...