Влияние сильного межузельного кулоновского взаимодействия на топологические свойства сверхпроводящей нанопроволоки

For superconducting nanowire with the pairing of extended s-type symmetry, Rashba spin-orbit interaction in a magnetic field, the influence of strong intersite charge correlations on single-particle Majorana excitations is analyzed. This problem is investigated on the basis of the density matrix renormalization group numerical method. It is shown that with an increase in the repulsion intensity of electrons located at the neighboring sites, two subbands emerge in the lower Hubbard band of the open system. Based on calculations of the Majorana polarization and degeneracy of the entanglement spectrum, it was found that a topologically nontrivial phase with one edge state survives at the edge of each of the subbands where the concentration of electrons or holes is minimal.

Evolution of correlated electron behavior from the surface to the bulk in SrxCa1-xVO3

ABSTRACTWe present a detailed depth-sensitive study of the evolution in correlated electron behavior from the surface of the prototypical correlated oxide, SrxCa1-xVO3, to its bulk. Photoemission measurements of varying surface sensitivity are employed to directly compare both the spectral weight and energetics of the correlated electron features, and resonant soft x-ray emission spectroscopy is used as a bulk-sensitive reference. The surface component, which still contributes significantly to photoemission at 2.2 keV, is characterized by a transfer of spectral weight into the incoherent lower Hubbard band and the corresponding shift of these states towards lower binding energy.

ELECTRONIC STRUCTURES OF THE METAL-TO-INSULATOR TRANSITION SYSTEM 1T-TaSxSe2-x STUDIED BY ANGLE-RESOLVED PHOTOEMISSION SPECTROSCOPY

We have investigated the electronic structures of metal-to-insulator transitions (MIT) due to charge-density-wave phase transition in 1T- TaS x Se 2-x by angle-resolved photoemission spectroscopy. In the insulating phase of the sample with x = 1.5, we observe a gap formation at the Fermi energy (E F ), while in the metallic phase of the sample with x = 1.2, we do not observe a drastic change in the spectra between at room temperature and at low temperature. We observe a peak originating from the lower Hubbard band in the insulating phase of the sample with x = 1.5. In the metallic phase of the sample with x = 1.2, the peak intensity is smaller and the peak energy shifts near E F , but the lower Hubbard band peak still remains. These results suggest that MIT in 1T- TaS x Se 2-x is due to the Mott localization.

THE ELECTRONS KINEMATIC INTERACTION AND HIGH-Tc SUPERCONDUCTIVITY IN TRANSITION METALS COMPOUNDS

In the strong short-ranged repulsion conditions the scattering picture of excitations is equivalent to the scattering of identical Fermi particles. In the wave lengths, large in comparison with the elementary cell dimensions (in Γ-point), the physical situation corresponds to the scattering of slow particles. For the latest case the scattering amplitude is positive always. With the energy increasing the scattering amplitude is decreases and changes his sign for momenta of order of inverse scattering centre dimension. In the crystal lattice the elementary cell dimension is the representative dimension. Hence we conclude that with energy increasing from Γ-point to the Brillouin zone boundary the scattering amplitude can to change the sign at the momentum of order of reciprical lattice vector . The negative sign of the scattering amplitude on the Fermi energy surface results to the normal state instability and the superconductivity condencate prescipitation. Therefore in the filling of lower Hubbard band the superconductivity begins from the some electrons finite concentration, corresponding to the amplitude sign change of the Fermi level.