© 2010-2014 SarFTI NRNU MEPhI

Dielectric permittivity and conductivity of hydrogen at isentropic compression up to 3 Mbar

Extreme state of matter

An evolution density of states in argon with xenon admixture and in pure argon under ultra-high pressures is shown. The small quantity of xenon cause metallization of the mixture.

The field estimation was 6 V for d =25 Е.

Model of magnetic ordering in magnetic superlattices  Fe/V

Theory of strongly correlated Fermi-systems

A variation theory of the strongly correlated state is a generalization of the Gutzwiller’s theory (closest neighbors are included). This theory allowed investigating the short-range order in the strongly correlated Fermi-systems.

Calculated magnetic structure of the superlattice [Fe(2)/V(12)/Fe(3)V(12)]20 at different temperatures. Red and blue color show Fe(3) and Fe(2) layers magnetization.

Magnetoelectric effect on palladium surface and in the structure Pd/BaO/Pd

A magnetoelectric effect is the magnetization change under the external electric field. It could be used for stimulation of a ferromagnetic (FM) state of a surface layer of almost ferromagnetic metal. In the theory of itinerant magnetism a transition of a paramagnetic metal to the FM phase is determined by the Stoner criterion. Palladium is a well-known example of almost ferromagnetic metal, in which the Stoner criterion is not fulfilled, but its value is very close to it. According to the estimations, DOS increase of bulk palladium on 10% should lead to fulfillment of the Stoner criterion and transition to the FM state. DOS change will be stimulated using an electric field.

Below one can see a supercell and DOS of the calculated structure (the dotted line shows a shift of the Fermi level)

Solid state physics and nanosystems

The Laboratory develops different theoretical models of electronic structure of strongly correlated and magnetic systems, and also the first-principle calculations.

Frustrated and low-dimensional magnetics and superconductors

There are several well-known  groups of magnetic compounds, where the triangular lattice is formed by Ising chains, for example in Ca3Co2O6. This compound has a step magnetization curve that depends on the temperature and sweep rate of the magnetic field. A theory of the magnetic structure and magnetization dynamics of Ca3Co2O6 has been developed within 2D and 3D  models..

Other results of  2D simulation of magnetization dynamics are presented here (files in AVI format):

• at temperature T=10K at the magnetic field rise time of  0.1 T/min
• at temperature T = 5 K at the magnetic field rise time of  0.01 T/min
• at temperature T = 10 K at the magnetic field rise time of  0.01 T/min

3D simulation of  of magnetization dynamics (file in AVI format):at temperature T=8K at the magnetic field rise time of  0.1 T/min (average magnetizations of chains are shown in color, magnetic moments arrangements in slices are shown at the bottom)

Nanosystems

Kondo-state of chromium trimers on a gold surface.

Structure of  the ground state of the equilateral chromium trimer bound with a gold surface

Below one can see an evolution of the magnetic structure Ca3Co2O6 in 2D model at temperature T=5K at the magnetic field sweep rate of 0.1 T/min. Black and white show directions of the magnetization chains. Formation of a domain structure is seen.