arXiv subjects

D. K. Loginov

Publications and source records attributed to D. K. Loginov.

4 recordsLinked to original sources

arXiv2026

Nonparabolic dispersion of charge carriers in CsPbI$_3$ in the orthorhombic phase

The dispersion curves for the electrons and holes in CsPbI$_3$ in the orthorhombic phase are calculated using the density functional theory (DFT), with the spin-orbit coupling taken into account. The effective masses of the charge carriers are obtained using the parabolic approximation of the dispersion curves in different directions in the $k$-space. It is found that the dispersion curves demonstrate strong nonparabolicity at energies above 0.2 eV for electrons and above 0.1 eV for holes, available for experimental study by the means of optical spectroscopy. We propose a model that describes the dispersion dependences of charge carriers at those energies, where the effective masses of the quasiparticles depend quadratically on the wave vector. An expression is obtained according to the model, which can accurately approximate the dispersion curves for the electron and the hole in all symmetric directions from the center to the boundary of the Brillouin zone.

cond-mat.mes-hall↗

arXiv2020

Exciton-polariton interference controlled by electric field

Linear in the wave-vector terms of an electron Hamiltonian play an important role in topological insulators and spintronic devices. Here we demonstrate how an external electric field controls the magnitude of a linear-in-K term in the exciton Hamiltonian in wide GaAs quantum wells. The dependence of this term on the applied field in a high quality sample was studied by means of the differential reflection spectroscopy. An excellent agreement between the experimental data and the results of calculations using semi-classical non-local dielectric response model confirms the validity of the method and paves the way for the realisation of excitonic Datta-and-Das transistors. In full analogy with the spin-orbit transistor proposed by Datta and Das [Appl. Phys. Lett. {\bf 56}, 665 (1990)], the switch between positive and negative interference of exciton polaritons propagating forward and backward in a GaAs film is achieved by application of an electric field with non-zero component in the plane of the quantum well layer.

cond-mat.mes-hall↗

arXiv2015

Decrease of heavy-hole exciton mass induced by uniaxial stress in GaAs/AlGaAs quantum well

It is experimentally shown that the pressure applied along the twofold symmetry axis of a heterostructure with a wide GaAs/AlGaAs quantum well leads to considerable modification of the polariton reflectance spectra. This effect is treated as the stress-induced decrease of the heavy-hole exciton mass. Theoretical modeling of the effect supports this assumption. The 5\%-decrease of the exciton mass is obtained at pressure P=0.23 GPa.

cond-mat.mes-hall↗

arXiv2014

Effect of uniaxial stress on the interference of polaritonic waves in wide quantum wells

A theory of polaritonic states is developed for a nanostructure with a wide quantum well stressed perpendicular to the growth axis of the heterostructure. The role of the $K$-linear terms appearing in the exciton Hamiltonian under the stress is discussed. Exciton reflectance spectra are theoretically modeled for the nanostructure. It is predicted that the spectral oscillations caused by interference of the exciton-like and photon-like polariton modes disappear with the increase of applied pressure and then appear again with opposite phase relative to that observed at low pressure. Effects of gyrotropy and convergence of masses of excitons with heavy and light holes due to their mixing by the deformation is also considered. Numerical estimates performed for the GaAs wells show that these effects can be experimentally observed at pressure $P < 1$~GPa for the well widths of a fraction of micron.

cond-mat.mes-hall↗