arXiv subjects

V. M. Muravev

Publications and source records attributed to V. M. Muravev.

17 recordsLinked to original sources

arXiv2026

Tunable massive and acoustic plasmons in two-dimensional plasmonic crystals

We theoretically investigate dispersion of plasma waves propagating in a lateral plasmonic crystal based on a two-dimensional electron system with grating gates. Two specific configurations are analyzed: a system with single grating gate having ungated gaps and a double-grating-gate system. We calculate the dispersion relations for the fundamental and several higher-order plasma modes, classifying them as either ${\it bright}$ or ${\it dark}$ excitations. At the boundaries of the Brillouin zones, the dispersion of both types of excitations is shown to be quadratic, justifying introduction of effective bright and dark plasmon masses. In the low-frequency limit, the plasmonic crystal spectrum exhibits an acoustic plasma mode characterized by a certain velocity. We demonstrate that the effective plasmon mass and acoustic velocity are highly sensitive to both the crystal geometry (specifically the lattice filling factor) and the gate voltages, enabling wide-range tunability.

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arXiv2026

Novel SuperLattice Plasmon Mode in a Grating of 2D Electron Strips

We investigate GaAs/AlGaAs heterostructure membranes with a metasurface made up of a grating of two-dimensional electron system (2DES) strips. Experiments have revealed a strong plasma resonance in the transmission of the metasurface. We have found that a collective effect from the superlattice, along with lateral screening between the strips, leads to the emergence of a new plasmon mode in the metasurface under study. Furthermore, we develop an analytical approach that accurately describes the behavior of the discovered superlattice plasmon mode, providing new insights into the fundamental physics of plasmonic metasurface systems.

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arXiv2025

Discovery of Slot Plasma Excitations in a AlGaN/GaN Plasmonic Crystal

We experimentally investigate the terahertz spectrum of plasma excitations in a plasmonic crystal based on AlGaN/GaN two-dimensional electron system (2DES). While screened plasmon modes with linear dispersion are readily observed in the plasmonic crystals, the existence of unscreened modes localized in the slots between the gates has remained unobserved until now. We discover this slot plasma excitation exhibiting square-root dispersion. It turned out that these slot plasmons follow an unconventional wave-vector quantization rule, $q_u=(N + 1/4) \times π/l_u$ for even integers $N$, and require the condition for excitation $q_u h \ll 1$, where $h$ is the gate-to-2DES distance and $l_u$ is the slot width. We develop an analytical model that accurately captures the found dispersion and relaxation, revealing a non-trivial $-π/4$ phase shift upon plasmon reflection at the gate edge. Experiments demonstrate that the slot plasmons persist up to room temperature, thereby enabling a broad range of opportunities for the advancement of plasmonic devices.

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arXiv2025

On the Nature of the Fundamental Plasma Excitation in a Plasmonic Crystal

We report on the experimental study of the spectrum of plasma excitations in a plasmonic crystal fabricated from the two-dimensional electron system in an AlGaAs/GaAs semiconductor heterostructure. We perform a comprehensive research on the mode frequency and relaxation as a function of the gate width across different plasmonic crystal periods. Importantly, we develop an analytical approach that accurately describes the behavior of plasma excitations in plasmonic crystals, providing new insights into the fundamental physics of plasmonic systems.

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arXiv2022

Plasmons in a Square of Two-Dimensional Electrons

Microwave absorption spectra of a single square of two-dimensional electrons (2DES) have been investigated using an optical detection technique. Fundamental dipole and harmonic quadrupole plasmon modes have been identified and compared to those in the disk geometry. In the square-shaped 2DES, a strong interaction is discovered between the neighboring plasmon modes, whereas no such hybridization is observed in the disk-shaped geometry. We establish a rigid theoretical platform to analytically describe the magneto-optical response of confined two-dimensional systems. The developed theory provides a proper description of the obtained experimental results.

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arXiv2021

Magnetodispersion of Two-Dimensional Plasmon Polaritons

We have investigated the spectrum of two-dimensional (2D) plasmon polaritons over the full range of magnetic fields. In our study, we investigate a disk-shaped two-dimensional electron system (2DES) with a metallic gate on the backside of the substrate. Importantly, we show that 2D plasmon polaritons hybridize with the TM$_0$ photonic mode of a dielectric waveguide formed by a sample substrate. We have developed a theory for plasmon-polaritons in an infinite 2DES. We find the experimental data to be in good agreement with the developed theory.

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arXiv2020

Piezoplasmonics: strain-induced tunability of plasmon resonance in AlAs quantum wells

We demonstrate tuning of two-dimensional (2D) plasmon spectrum in modulation-doped AlAs quantum wells via the application of in-plane uniaxial strain. We show that dramatic change in the plasma spectrum is caused by strain-induced redistribution of charge carriers between anisotropic $X_x$ and $X_y$ valleys. Discovered piezoplasmonic effect provides a tool to study the band structure of 2D systems. We use piezoplasmonic effect to measure how the inter-valley energy splitting depends on the deformation. This dependency yields the AlAs deformation potential of $E_2 = (5.6 \pm 0.3)$~eV.

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arXiv2020

A tunable plasmonic resonator using kinetic 2D inductance and patch capacitance

We have studied microwave response of a high-mobility two-dimensional electron system (2DES) contacted by two side electrodes. Using kinetic inductance of the 2DES and inter-electrode capacitance, we have constructed a subwavelength 2D plasmonic resonator. We have shown that the resonant frequency of this circuit can be controlled by 2D electron density, external magnetic field, or size of the electrodes. This opens up possibilities for using arrays of plasmonic circuits as tunable components in different frequency ranges.

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arXiv2019

Novel 2D Plasmon Induced by Metal Proximity

A new electromagnetic plasma mode has been discovered in the hybrid system formed by a highly conductive gate strip placed in proximity to the two-dimensional electron system. The new plasmon mode propagates along the gate strip with no potential nodes present in transverse direction. Its unique spectrum combines characteristic features of both gated and ungated 2D plasmons. The new plasma excitation has been found to exhibit anomalously strong interaction with light.

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arXiv2019

Achieving Balance of Valley Occupancy in Narrow AlAs Quantum Wells

Terahertz photoconductivity of $100~μ$m and $20~μ$m Hall bars fabricated from narrow AlAs quantum wells (QWs) of different widths is investigated in this paper. The photoresponse is dominated by collective magnetoplasmon excitations within the body of the Hall structure. We observed a radical change of magnetoplasma spectrum measured precisely for AlAs QWs of width ranging from $4$~nm up to $15$~nm. We have shown that the observed behavior is a vivid manifestation of valley transition taking place in the two-dimensional electron system. Remarkably, we show that photoresponse for AlAs QWs of width $6$~nm features two resonances, indicating simultaneous occupation of strongly anisotropic $X_{x-y}$ valleys and isotropic $X_z$ valley in the QW plane. Our results pave the way to realizing valley-selective layered heterostructures, with potential application in valleytronics.

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arXiv2018

Direct observation of $Γ- X$ energy spectrum transition in narrow AlAs quantum wells

Spectra of magnetoplasma excitations have been investigated in a two-dimensional electron systems in AlAs quantum wells (QWs) of different widths. The magnetoplasma spectrum have been found to change profoundly when the quantum well width became thinner than $5.5$~nm, indicating a drastic change in the conduction electron energy spectrum. The transformation can be interpreted in terms of transition from the in-plane strongly anisotropic $X_x - X_y$ valley occupation to the out-of-plane isotropic $X_z$ valley in the QW plane. Strong enhancement of the cyclotron effective mass over the band value in narrow AlAs QWs is reported.

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arXiv2018

Drastic Reduction of Plasmon Damping in Two-Dimensional Electron Disks

The plasmon damping has been investigated using resonant microwave absorption of two-dimensional electrons in disks with different diameters. We have found an unexpected drastic reduction of the plasmon damping in the regime of strong retardation. This finding implies large delocalization of retarded plasmon field outside the plane of the two-dimensional electron system. A universal relation between the damping of plasmon polariton waves and retardation parameter is reported.

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arXiv2017

Azbel'-Kaner-Like Cyclotron Resonance in a Two-Dimensional Electron System

Resonant microwave absorption of a two-dimensional electron system in an AlGaAs/GaAs heterostructure excited by a near-field technique was investigated. Along with collective magnetoplasmon modes, we observed resonance that precisely follows the cyclotron resonance (CR) position and revealed no signs of collective plasma depolarization shift. We show that the discovered CR mode is absent in the Faraday geometry, and is localized at the edge of the exciting metal electrode. Such behavior points in favor of the single-particle Azbel'-Kaner nature of the discovered resonance.

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arXiv2016

Fine Structure of Cyclotron Resonance in a Two-Dimensional Electron System

It is established that cyclotron resonance (CR) in a high-quality GaAs/AlGaAs two-dimensional electron system (2DES) originates as a \textit{pure} resonance, that does not hybridize with dimensional magnetoplasma excitations. The magnetoplasma resonances form a fine structure of the CR. The observed fine structure of the CR results from the interplay between coherent radiative and incoherent collisional mechanisms of 2D plasma relaxation. We show that the range of 2DES filling factors from which the phenomenon arises is intimately connected to the fundamental fine-structure constant.

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arXiv2015

Dispersion of Volume Relativistic Magnetoplasma Excitation in a Gated Two-Dimensional Electron System

The dispersion of the volume relativistic magnetoplasma mode in a gated GaAs/AlGaAs quantum well is measured using a coupled resonators detection technique. The weakly damped relativistic mode exhibits an unusual zigzag-shaped magnetodispersion dependence dictated by the diagonal component of the resistivity tensor $ρ_{xx}$. The plasma excitation easily hybridizes with photon modes due to a large spatial delocalization of its electromagnetic field. The effects of electron density and structure geometry on the excitation spectrum have been investigated.

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arXiv2015

Magnetoplasma excitations of two-dimensional anisotropic heavy fermions in AlAs quantum wells

The spectra of plasma and magnetoplasma excitations in a two-dimensional system of anisotropic heavy fermions were investigated for the first time. The spectrum of microwave absorption by disk-like samples of stressed AlAs quantum wells at low electron densities showed two plasma resonances separated by a frequency gap. These two plasma resonances correspond to electron mass principle values of $(1.10 \pm 0.05) m_0$ and $(0.20 \pm 0.01) m_0$. The observed results correspond to the case of a single valley strongly anisotropic Fermi surface. It was established that electron density increase results in population of the second valley, manifesting itself as a drastic modification of the plasma spectrum. We directly determined the electron densities in each valley and the inter-valley splitting energy from the ratio of the two plasma frequencies.

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arXiv2015

Novel relativistic plasma excitations in a gated two-dimensional electron system

The microwave response of a two-dimensional electron system (2DES) covered by a conducting top gate is investigated in the relativistic regime for which the 2D conductivity $σ_{2 \rm{D}} > c/2π$. Weakly damped plasma waves are excited in the gated region of the 2DES. The frequency and amplitude of the resulting plasma excitations show a very unusual dependence on the magnetic field, conductivity, gate geometry and separation from the 2DES. We show that such relativistic plasmons survive for temperatures up to 300 K, allowing for new room-temperature microwave and terahertz applications.

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