arXiv subjects

S. V. Iordanski

Publications and source records attributed to S. V. Iordanski.

13 recordsLinked to original sources

arXiv2015

On the origin of the transversal current in double layered heterostructures

It is shown that usually used theoretical model for double layered heterostructures as a pseudospin ferromagnet, does not give the observed two dimensional spectrum. Its existence is possible only neglecting Coulomb interaction destroying two dimensional structures and can be realized only in a strong magnetic field. That is connected also with the plain vortex lattices arising at strong magnetic field due to thermodynamic instability. This model gives the reasonable explanations of various observed effects depending on the filling of the corresponding bands.In particular in this work we show that in double layered heterostructures can exist large inter layer conductance really observed.

cond-mat.str-el↗

arXiv2014

The conductivity of the half filled Landau level

It is shown that the thermodynamic instability at the half filling of Ll leads to the vortex lattice formation with the electronic spectrum analogous to that of graphene with two Dirac Fermi points on Brillouin cell boundary. This result is used for the explanation of the observed current generated by SAW in the heterostructure on the surface of piezoelectric GaAs. Using the existence of two Fermi points instead Fermi surface suggested in the previous theoretical works, permit the explanation of the experimental results.

cond-mat.mes-hall↗

arXiv2013

The flow around a macroscopical body by a colloid solution and the drag crisis

The motion of colloids in the flow field of a viscous liquid is investigated. The small colloid size compare to the macroscopical scale of the flow allow to calculate their velocity relative to that of the liquid. If the inner colloid density is larger then the density of the liquid the flow field has the domains where the colloid velocity is close to the liquid velocity. But in the domains with a strong braking of the liquid velocity the colloids are accelerated relative to the liquid. This effect is used for the qualitative explanation of the drag reduction in the flow around macroscopical bodies and in the pipes.

nlin.AO↗

arXiv2011

The lattices with the continious vorticity as a model for FQHE

It was shown that the including spin of 2d electrons at high magnetic field is possible to remove the divergencies in the cores of the vortex lattice and construct the topologically stable states. These states can be considered as the lattices of skyrmions where the unit cell is mapped on the whole sphere of spin directions.That gives the gapped ground state for electrons and can be used as a model for FQHE.

cond-mat.mes-hall↗

arXiv2009

Fractional Quantum Hall Effect and vortex lattices.II

It is demonstrated that all observed fractions at moderate Landau level fillings for the quantum Hall effect can be obtained without recourse to the phenomenological concept of composite fermions. The possibility to have the special topologically nontrivial many-electron wave functions is considered. Their group classification indicates the special values of of electron density in the ground states separated by a gap from excited states. These gaps were calculated for some lattices in a simplified model.

cond-mat.mes-hall↗

arXiv2008

Fractional Quantum Hall Effect and vortex lattices

cond-mat.mes-hall↗

arXiv2004

Fractional Quantum Hall Effect and vortex lattices

It is demonstrated that all observed fractions at moderate Landau level fillings in the quantum Hall effect can be obtained without recourse to the phenomenological concept of composite fermions. The possibility to have the special topologically nontrivial many-electron wave functions is considered. Their group classification indicate the special values of of electron density in the ground states separated by a gap from excited energies.

cond-mat.mes-hall↗

arXiv2002

Possible Jahn-Teller effect in Si-inverse layers

Jahn-Teller effect in bivalley Si(100) MOSFET under conditions of quantum Hall effect at integer filling factors nu=1,2,3 is studied. This system is described by SU(4) hidden symmetry. At nu=2 static and dynamic lattice deformation creates an easy-plane anisotropy and antiferromagnetic exchange and lifts the valley degeneracy. At nu=1,3 Coulomb interaction is essential to produce weak easy-plane anisotropy. Three phases: ferromagnetic, canted antiferromagnetic and spin-singlet, have been found. Anisotropy energy of charged skyrmion excitation in every phase is found.

cond-mat.mes-hall↗

arXiv2002

Multicomponent dense electron gas as a model of Si MOSFET

We solve two-dimensional model of $N$-component dense electron gas in the limit of large $N$ and in a range of the Coulomb interaction parameter: $N^{-3/2}\ll r_s\ll 1$. The quasiparticle interaction on the Fermi circle vanishes as 1/N. The ground state energy and the effective mass are found as series in powers of $r_s^{2/3}$. In the quantum Hall state on the lowest Landau level at integer filling: $1\llν<N$, the charge activation energy gap and the exchange constant are found.

cond-mat.mes-hall↗

arXiv2001

Low temperature kinetics of 2D exciton gas cooling in quantum well bilayer

We study the kinetics of 2D Bose gas cooling provided Bose particles interact with 3D phonons. At low temperatures phonon emission is prohibited by the energy and the momentum conservation. We show that both particle-particle scattering and impurity scattering assist the Bose gas cooling.

cond-mat.mes-hall↗

arXiv2000

Electron - hole asymmetry and activation energy in quantum Hall ferromagnets

We argue that the dissipative transport in ferromagnetic quantum Hall effect liquids at $ν=2N+1$ is dominated by the thermal activation of pairs consisting of an electron and an antiskyrmion (topological texture which represents a hole with 'screened' exchange interaction), thus manifesting the lack of electron-hole symmetry in quantum Hall ferromagnets. We find that the activation energy of such a pair is not the exchange energy, but is determined by the interplay between the excess Zeeman energy of a skyrmion and the charging energy of its topological texture: $${\cal E}=aε_{\rm Z}^{1/3}E_{\rm C}^{2/3}\ln ^{1/3}(\frac{\Im_{i}}{E_{\rm C}^{2/3}ε_{\rm Z}^{1/3}}), E_{\rm C}=\frac{e^{2}}{χλ}, $$ with $ a\approx 1.75$.

cond-mat.mes-hall↗

arXiv2000

Conductivity activation energy for bilayer hetero-structures at integer filling numbers

We report on study of low-energy excitations in a bilayer hetero-structure 2D electron gas. We split the bilayer Hamiltonian into SU(4)-symmetric part and the anisotropy part and treat the latter as a perturbation. We find that both Goldstone and the charged excitations - skyrmions - are goverened by the non-linear Sigma Model. We calculate the anisotropic energy gap of the skyrmion to have a prominent minimum in the canted antiferromagnetic phase of bilayer. We compare our findings with the results of recent experiments.

cond-mat.mes-hall↗

arXiv1999

Spin-orbit coupling effect on quantum Hall ferromagnets with vanishing Zeeman energy

We present the phase diagram of a ferromagnetic quantum Hall effect liquid in a narrow quantum well with vanishing single-particle Zeeman splitting, $ε_{\rm Z}$ and pronounced spin-orbit coupling. Upon decreasing $ε_{\rm Z}$, the spin-polarization field of a liquid takes, first, the easy-axis configuration, followed by the formation of a helical state, which affects the transport and NMR properties of a liquid and the form of topological defects in it. The analysis is extended over high odd integer filling factors.

cond-mat.mes-hall↗