arXiv subjects

Mikhail A. Kaliteevski

Publications and source records attributed to Mikhail A. Kaliteevski.

5 recordsLinked to original sources

arXiv2023

Competition of moiré network sites to form electronic quantum dots in reconstructed MoX${}_2$/WX${}_2$ heterostructures

Twisted bilayers of two-dimensional semiconductors offer a versatile platform to engineer quantum states for charge carriers using moiré superlattice effects. Among the systems of recent interest are twistronic MoSe${}_{2}$/WSe${}_{2}$ and MoS${}_{2}$/WS${}_{2}$ heterostructures, which undergo reconstruction into preferential stacking domains and highly strained domain wall networks, determining the electron/hole localization across moiré superlattices. Here, we present a catalogue of options for the formation of self-organized quantum dots and wires in lattice-reconstructed marginally twisted MoSe${}_{2}$/WSe${}_{2}$ and MoS${}_{2}$/WS${}_{2}$ bilayers, fine tuned by the twist angle between the monolayers from perfect alignment to $θ\sim 1^{\circ}$, and by choosing parallel or anti-parallel orientation of their unit cells. The proposed scenarios of the quantum dots and wires formation are found using multi-scale modelling that takes into account the features of strain textures caused by twirling of domain wall networks.

cond-mat.mes-hall↗

arXiv2020

Proposal for photoacoustic ultrasonic generator based on Tamm plasmon structures

The scheme of generation of ultrasound waves based on optically excited Tamm plasmon structures is proposed. It is shown that Tamm plasmon structures can provide total absorption of a laser pulse with arbitrary wavelength in a metallic layer providing the possibility of the use of an infrared semiconductor laser for the excitation of ultrasound waves. Laser pulse absorption, heat transfer and dynamical properties of the structure are modeled, and the optimal design of the structure is found. It is demonstrated that the Tamm plasmon-based photoacoustic generator can emit ultrasound waves in the frequency band up to 100 MHz with pre-defined frequency spectrum. Optical power to sound power conversion efficiency grows linearly with frequency of the laser modulation and excitation power.

physics.app-ph↗

arXiv2020

Control of the surface plasmon dispersion and Purcell effect at the metamaterial-dielectric interface

The use of metamaterial as a way to mitigate the negative effects of absorption in metals on the Purcell effect in metal-dielectric structures is investigated. A layered metal-dielectric structure is considered as an anisotropic medium in the long-wavelength limit. The dispersion of the surface plasmon appearing at the boundary between such a structure and a different dielectric material, as well as the position of the peak in the local density of states are studied for various combinations of materials and filling factors of the periodic structure. The calculated frequency dependence of the Purcell factor demonstrates an increase in peak value compared to the conventional plasmonic structure.

physics.optics↗

arXiv2019

Modification of Excitonic Emission in GaN Microcavities Formed by Planar Hexagonal Micro-Nuts Grown by Selective Area Epitaxy

GaN-based resonators supporting whispering gallery modes are suggested as a promising approach for fabrication of efficient nanophotonic applications. A modification of excitonic emission due to coupling with cavity modes is observed experimentally in the GaN planar hexagonal microcavities grown by a selective area metal-organic vapor phase epitaxy. Low temperature cathodoluminescence spectra measured in-situ scanning electron microscope show two or three emission peaks split by 100 meV or 160 meV for the resonators formed by double- and single-wall micro-nuts, respectively. The results are compared with numerical calculations of the cavity mode energies, their Q-factors and the spatial distribution of the modes intensities. Although most modes are characterized by a small Purcell coefficient, there are a limited number of isolated cavity modes with a large Purcell factor. Such modes can efficiently interact with the bulk exciton in GaN. The results are also analyzed by diagonalization of Hamiltanion describing the system of interacting exciton and cavity modes. Theoretically, it is shown that a strong coupling between the exciton and the cavity modes is possible in such micro-resonators.

physics.app-ph↗

arXiv2019

Enhancement of light emission in Bragg monolayer-thick quantum well structures

Control over spontaneous emission rate is important for improving efficiency in different semiconductor applications including lasers, LEDs and photovoltaics. Usually, an emitter should be placed inside the cavity to increase spontaneous emission rate, although it is technologically challenging. Here we experimentally demonstrate a phenomenon of super-radiance observed in a cavity-less periodic Bragg structure based on InAs monolayer-thick multiple quantum wells (MQW). The collective super-radiant mode shows enhanced emission rate for specific angles and frequencies. This behaviour correlates with the calculations demonstrating individual spots of enhanced Purcell coefficient near the Bragg condition curve. This study provides a perspective for realization of surface emitting cavity-less lasers with distributed feedback.

cond-mat.mes-hall↗