arXiv subjects

L. S. Braginsky

Publications and source records attributed to L. S. Braginsky.

8 recordsLinked to original sources

arXiv2026

Theory of transmittance of narrow quantum wires intersection in 2D systems

Two-dimensional nanosystems the characteristic sizes of which are less than the quasiparticle wavelength have been studied. This parameter allows replacement of the Shrödinger equation by the Laplace one. The latter permits us exact solution using the conformal mapping technique. Bulged 1D quantum wires based on 2D system are considered. The electron states in these systems have been studied. The transmittance of the intersection between the narrow quantum strips has been studied. It is assumed that strip widths are less than the electron wavelength, so that they are the tunnel conductors. The transmittances of T-like and X-like wire crossings have been found.

cond-mat.mes-hall↗

arXiv2023

Orbital momentum excitation by interband optical transitions in a 2D system illuminated by twisted light

Illumination of a two-dimensional system by a twisted light beam is considered in order to find specific effects caused by twisting. Direct interband transitions between the valence and conduction bands are supposed. The generation rates of the electron orbital momentum is found. A kinetic equation for an orbital momentum distribution function is formulated and solved. The mean electron orbital momentum is found.

cond-mat.mes-hall↗

arXiv2017

Exact solution for many-body Hamiltonian of interacting particles with linear spectrum

The exact solution of the Schrödinger equation for the one-dimensional system of interacting particles with the linear dispersion law in an arbitrary external field is found. The solution is reduced to two groups of particles moving with constant velocities in the opposite directions with a fixed distance between the particles in each group. The problem is applied to the edge states of the 2D topological insulator.

cond-mat.mes-hall↗

arXiv2017

Edge capacitance of a 2D topological insulator

We study capacitance of the 2D topological insulator (TI) edge states. The total capacitance is combined as a serial circuite of 3 capacitors presenting geometrical $C_G$, quantum $C_Q$ and correlation $C_{corr}$ contributions to the electron energy. If the Coulomb interaction is weak, they obey an inequality $C_G<C_Q<C_{corr}$. Quantities $C_G$ and $C_Q$ are found in the case of a round TI dot. The quantum capacitance at the finite temperature is determined taking into account the edge states quantization with and without the magnetic field. We have concluded that, in the accepted approximations, $C_{corr}=0$.

cond-mat.mes-hall↗

arXiv2014

Intervalley scattering by charged impurities in graphene

Intervalley charged-impurity scattering processes are examined. It is found that the scattering probability is enhanced due to the Coulomb interaction with the impurity by the Sommerfield factor $F_Z\propto ε^{2\sqrt{1-4g^2}-2}$, where $ε$ is the electron energy and $g$ is the dimensionless constant of the Coulomb interaction.

cond-mat.mes-hall↗

arXiv2011

Influence of the heterointerface sharpness on exciton recombination dynamics in an ensemble of (In,Al)As/AlAs quantum dots with indirect band-gap

The dynamics of exciton recombination in an ensemble of indirect band-gap (In,Al)As/AlAs quantum dots with type-I band alignment is studied. The lifetime of confined excitons which are indirect in momentum-space is mainly influenced by the sharpness of the heterointerface between the (In,Al)As quantum dot and the AlAs barrier matrix. Time-resolved photoluminescence experiments and theoretical model calculations reveal a strong dependence of the exciton lifetime on the thickness of the interface diffusion layer. The lifetime of excitons with a particular optical transition energy varies because this energy is obtained for quantum dots differing in size, shape and composition. The different exciton lifetimes, which result in photoluminescence with non-exponential decay obeying a power-law function, can be described by a phenomenological distribution function, which allows one to explain the photoluminescence decay with one fitting parameter only.

cond-mat.mes-hall↗

arXiv2008

High-frequency blockade and related phenomena

We study systems with local vibrating potentials, one-dimensional single and double wells and the tight-binding 1D model with single vibrating site. In general, these systems transmit, or reflect particles inelastically, with absorption or emission of several frequency quanta. Nevertheless, we have found that at some conditions these systems can perfectly and elastically reflect electrons. This high-frequency "blockade" give rise to unique possibility of near-ideal localization of electron with the energy lying on the background of continuous energy spectrum. We discuss different consequences of this statement.

cond-mat.mes-hall↗

arXiv2000

Kinetics of exciton photoluminescence in type-II semiconductor superlattices

The exciton decay rate at a rough interface in type-II semiconductor superlattices is investigated. It is shown that the possibility of recombination of indirect excitons at a plane interface essentially affects kinetics of the exciton photoluminescence at a rough interface. This happens because of strong correlation between the exciton recombination at the plane interface and at the roughness. Expressions that relate the parameters of the luminescence kinetics with statistical characteristics of the rough interface are obtained. The mean height and length of roughnesses in GaAs/AlAs superlattices are estimated from the experimental data.

cond-mat.mes-hall↗