arXiv subjects

Vladimir N. Mantsevich

Publications and source records attributed to Vladimir N. Mantsevich.

8 recordsLinked to original sources

arXiv2026

Proximity effects of chiral magnetization on transition metal dichalcogenides monolayers

We consider the proximity effects of a commensurate chiral $120^{\circ}$ Néel magnetic structure on the transport and optical properties of a transition metal dichalcogenide monolayer (TMD ML). The enlarged magnetic unit cell leads to the folding of the Brillouin zone and enables efficient intervalley spin-flip scattering. Starting from a six band tight binding model, we develop an effective $k\cdot p$ model, which describes the coupling between charge carriers in the TMD ML and the chiral magnetization. We predict the anomalous antiferromagnetic Hall effect (AHE) for conduction electrons and describe it accounting for the interplay between anomalous velocity, side jump, and skew scattering contributions. The proximity of the chiral magnetization also leads to the mixing and splitting of the exciton resonances in the two valleys which are related by the time reversal symmetry despite zero net magnetization. Finally, we demonstrate the possibility to measure the distribution of in-plane orientation of the chiral magnetization through Faraday rotation and the ellipticity of incident linearly polarized light.

cond-mat.mes-hall↗

arXiv2026

Valley-controlled chiral magnetism in transition metal dichalcogenide monolayers

We put forward the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in transition metal dichalcogenide monolayers as a tool to create and control a chiral magnetic texture. We show that in the spin-valley locking regime, the RKKY interaction acts as a Dzyaloshinskii-Moriya coupling with an effective spin rotation period exactly equal to the tripled lattice constant. Using mean field theory and classical Monte Carlo simulations, we demonstrate that this interaction qualitatively reshapes the phase diagram of atomically thin antiferromagnets. It destroys the chirality-related phase transition by selecting a single chirality value even when the RKKY interaction is small. At the same time, it shifts the Berezinskii-Kosterlitz-Thouless transition associated with spins orientation to higher temperatures. We argue that the valley degree of freedom of electrons mediating the RKKY interaction provides a powerful control knob for exploring non-universal phase transitions and quantum spin liquid states in two-dimensional van der Waals heterostructures.

cond-mat.mes-hall↗

arXiv2024

Diffusion of fast and slow excitons with an exchange in quasi-two-dimensional systems

By means of analytical calculations and numerical simulations we study the diffusion properties in quasi-two-dimensional structures with two exciton subsystems with an exchange between them. The experimental realisation is possible in systems where fast and slow exciton subsystems appear. For substantially different diffusion coefficients of the species the negative diffusion can be observed, if one measures the transport properties of only a single subsystem, just as was obtained in experimental studies for quasi-two-dimensional semiconductor systems. The initial transition from a fast subsystem to a slow one results in a delayed release of fast excitons in the area close to the original excitation spot. Hence, the signal from the fast excitons alone includes the delayed replenishment from the transition of slow quasi-particles. This is seen as the narrowing of the exciton density profile or decrease of mean-squared displacement which is then interpreted as a negative diffusion. The average diffusion coefficients for the combined population are analytically expressed through the diffusion coefficients of fast and slow excitons. Simple analytical expressions for effective diffusion coefficients obtained in limiting cases are of interest both for theoretical and experimental analysis of not only the exciton transport, but also for a variety of systems, where fast and slow moving subsystems are present.

cond-mat.stat-mech↗

arXiv2023

Negative diffusion of excitons in quasi-two-dimensional systems

We show how two different mobile-immobile type models explain the observation of negative diffusion of excitons reported in experimental studies in quasi-two-dimensional semiconductor systems. The main reason for the effect is the initial trapping and a delayed release of free excitons in the area close to the original excitation spot. The density of trapped excitons is not registered experimentally. Hence, the signal from the free excitons alone includes the delayed release of not diffusing trapped particles. This is seen as the narrowing of the exciton density profile or decrease of mean-squared displacement which is then interpreted as a negative diffusion. The effect is enhanced with the increase of recombination intensity as well as the rate of the exciton-exciton binary interactions.

cond-mat.mes-hall↗

arXiv2021

Complex diffusion-based kinetics of photoluminescence in semiconductor nanoplatelets

We present a diffusion-based simulation and theoretical models for explanation of photoluminescence (PL) emission intensity in semiconductor nanoplatelets. It is shown that the shape of PL intensity curves can be reproduced by the interplay of recombination, diffusion and trapping of excitons. The emission intensity at short times is purely exponential and is defined by recombination. At long times it is governed by the release of excitons from surface traps and is characterized by a power-law tail. We show that the crossover from one limit to another is controlled by diffusion properties. This intermediate region exhibits a rich behaviour depending on the value of diffusivity. Proposed approach reproduces all the features of experimental curves measured for different nanoplatelet systems.

cond-mat.mes-hall↗

arXiv2020

Exciton-Exciton Interaction and Cascade Relaxation of Excitons in Colloidal CdSe Nanoplatelets

We experimentally investigated for the first time the lowest four band structure of Cd Se nanoplatelets at the r point of Brillouin zone [heavy-hole (hh), light-hole (lh) and two spin-orbital bands] and its modification due to the changing of the CdS shell thickness. The results of an experimental and theoretical study of exciton dynamics in colloidal CdSe/CdS nanoplateles are presented in the case of stationary laser excitation. The excitation was performed by means of the powerful nanosecond laser and the pump and probe technique was utilized. The differential transmission spectra peculiarities

cond-mat.mes-hall↗

arXiv2017

Comparison of pure and combined search strategies for single and multiple targets

We address the generic problem of random search for a point-like target on a line. Using the measures of search reliability and efficiency to quantify the random search quality, we compare Brownian search with Lévy search based on long-tailed jump length distributions. We then compare these results with a search process combined of two different long-tailed jump length distributions. Moreover, we study the case of multiple targets located by a Lévy searcher.

cond-mat.stat-mech↗

arXiv2017

Fluid photonic crystal from colloidal quantum dots

We study optical forces acting upon semiconductor quantum dots and the force driven motion of the dots in a colloid. In the spectral range of exciton transitions in uantum dots, when the photon energy is close to the exciton energy, the polarizability of the dots is drastically increased. It leads to a resonant increase of both the gradient and the scattering contributions to the optical force, which enables the efficient manipulation with the dots. We reveal that the optical grating of the colloid leads to the formation of a fluid photonic crystal with spatially periodic circulating fluxes and density of the dots. Pronounced resonant dielectric response of semiconductor quantum dots enables a separation of the quantum dots with different exciton frequencies.

cond-mat.mes-hall↗