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Luminescence in nanostructures with compensated quantum wells under optical and electrical pumping
St. Petersburg Polytechnical University Journal: Physics and Mathematics. 2024. Vol. 17. No. 1.1. P. 68–76.
Adamov R. B., Melentev G. A., Podoskin A. A., Slipchenko S. O., Sedova I. V., Sorokin S. V., Makhov I., Firsov D. A., Shalygin V. A.
Comprehensive studies of the luminescence of p–i–n structures with 10 compensated GaAs/AlGaAs quantum wells have been performed. The studies were carried out in the terahertz (THz) and near-infrared (NIR) spectral ranges with both optical and electrical pumping of nonequilibrium charge carriers. The THz photoluminescence spectra revealed an emission line caused by electron transitions from the first size-quantization subband e1 to the ground levels of donors D1s. The photo- and electroluminescence spectra in the NIR range revealed an emission line caused by electron transitions from the D1s levels to the first subband of heavy holes hh1. These transitions provide effective depletion of the D1s levels and are therefore relevant for creating a THz emitter operating at e1–D1s transitions. At high injection currents in the p–i–n diode, lasing occurs at the D1s–hh1 transitions, which increases the efficiency of depletion of the D1s levels. It is shown that for a given optical pump power or injection current density, the overall rate of the D1s–hh1 transitions in the p–i–n structure with 10 QWs is significantly higher than in similar structure with 50 QWs.
D.V. Khomitsky, Lavrukhina E. A., Krasavin D. P. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 22 Article 225414
We study coherent electric manipulation of magnetic field induced localized states at a double kink of a helical edge in a HgTe/CdHgTe quantum well. An in-plane magnetic field opens a gap in the one-dimensional (1D) edge spectrum, while changes in the edge orientation generate localized in-gap states at the kinks. We show that, for suitable ...
Added: October 23, 2026
Budkov Y., Kalikin N., Journal of Chemical Physics 2026 Vol. 165 No. 16 Article 164108
We derive the local pressure tensor generated by the original Rosenfeld fundamental measure theory (FMT) for hard-sphere fluids from an arbitrary infinitesimal deformation. The variation of a finite-distance FMT kernel is written via the line integrals of the local deformation gradient along the straight segment connecting its end points. The resulting symmetric pressure tensor consists ...
Added: October 22, 2026
Ивченко В. С., Иевлева В. А., Matienko D. et al., Журнал технической физики 2026 № 9 С. 1738–1749
Задача о возбуждении бегущих фонон-поляритонных волн на поверхности полярного кристалла падающей извне световой волной (с частотой, близкой к частоте решеточных колебаний) решена теоретически только для бесконечной открытой поверхности кристалла. В случаях, когда часть поверхности покрыта металлической маской, препятствующей проникновению возбуждающего излучения к атомам среды, и эта маска имеет произвольную форму, общепризнанного решения неоднородной задачи нет. ...
Added: October 20, 2026
Logvenkov S. A., Известия РАН. Механика жидкости и газа 2026 № 3 С. 59–75
The problem of the evolution of cell volume fraction in a spherical aggregate composed of cells,
extracellular matrix, and fluid is considered. The aggregate is surrounded by extracellular matrix. The
problem formulation employs a multiphase model of a biological continuum, previously developed by the
author, consisting of two actively interacting solid phases and a fluid. The propagation of ...
Added: October 20, 2026
Lavrukhina E. A., Krasavin D. P., Krishtopenko S. S. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 22 Article 225414
We study coherent electric manipulation of magnetic field induced localized states at a double kink of a helical edge in a HgTe/CdHgTe quantum well. An in-plane magnetic field opens a gap in the one-dimensional (1D) edge spectrum, while changes in the edge orientation generate localized in-gap states at the kinks. We show that, for suitable ...
Added: October 19, 2026
Смерчанский П. С., Koledov V. V., Kamantsev A. P. et al., Physics of Metals and Metallography 2026 Vol. 127 No. 6-7 P. 689–693
Heusler alloys of the Ni2MnX family, where X = Ga, In, Sn, …, which have been shown to exhibit
giant magnetocaloric effect (MCE) and magnetically controlled shape memory effect due to thermoelastic
magnetostructural phase transition (MSPT), continue to attract attention. However, these functional properties are fully manifested in strong magnetic fields of at least several T. Currently, ...
Added: October 19, 2026
Zaikin A., Kalenkov M. S., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 Article 214502
We propose a microscopic scheme that allows to describe ac Josephson effect in superconducting junctions
in terms of dissipative quantum dynamics of subgap Andreev bound states. This approach is particularly useful
for highly transparent junctions at subgap bias voltages in which case a nontrivial combination of Landau-Zener
tunneling between Andreev levels and their instability due to quasiparticle escape ...
Added: October 18, 2026
Zaikin A., Kalenkov M. S., Physical Review Letters 2026 Vol. 137 Article 076004
With the aid of a microscopic theory we derive an effective Hamiltonian that controls quantum dynamics
of Andreev states in superconducting nanojunctions out of equilibrium. Resolving the corresponding
Schrödinger-like equation we obtain the “wave functions” for Andreev levels and evaluate electric current
across the junction in the presence of an external voltage bias.We demonstrate that quantum interference of
Andreev ...
Added: October 18, 2026
Тукачев Н. В., Bataev V., Abramenkov A. et al., Computational and Theoretical Chemistry 2016 No. 1080 P. 23–32
Electronic state calculations, such as equilibrium geometry parameters, harmonic vibrational frequencies and potential barriers to conformational transitions (as well as conformer energy differences in excited states), using ab initio methods, such as MP2, CCSD(T), CASSCF, CASPT2 and MRCI, were carried out on the formamide molecule in the ground (S0) and the lowest excited singlet (S1) ...
Added: October 14, 2026
Тукачев Н. В., Bataev V. А., Godunov I. А., Journal of Quantitative Spectroscopy and Radiative Transfer 2016 Vol. 177 P. 291–300
For conformers of the N-methylformamide (HCONHCH3) molecule, calculations of equilibrium geometry parameters, harmonic vibration frequencies, energy differences and potential barriers to conformational transitions were performed in the ground (S0) and lowest excited singlet (S1) and triplet (T1) electronic states. In the S0 state, the molecule exists in trans and cis stable conformations (having Cs symmetry). ...
Added: October 14, 2026
Тукачев Н. В., Bataev V. А., Godunov I. А., Journal of Quantitative Spectroscopy and Radiative Transfer 2017 Vol. 192 P. 30–41
For acetamide molecule (CH3CONH2) in the ground (S0) and lowest excited singlet (S1) and triplet (T1) electronic states calculations of equilibrium geometry parameters, harmonic vibrational frequencies and barriers to conformational transitions (also conformer energy differences in excited states) using following ab initio methods: MP2, CCSD(T), CASSCF, CASPT2 and MRCI were performed. One-, two- and three-dimensional ...
Added: October 14, 2026
Тукачев Н. В., Bataev V. A., Godunov I. A., Computational and Theoretical Chemistry 2017 Vol. 1113 P. 82–93
Equilibrium geometry parameters, harmonic vibrational frequencies and barriers to conformational transitions and conformer energy differences for N-methylacetamide (CH3CONHCH3) molecule in S0, S1 and T1 electronic states were calculated in MP2 (S0) and CASPT2 (S1, T1) levels of theory. It is known that there are two planar (or effectively planar) conformers of N-methylacetamide in the ground ...
Added: October 14, 2026
Тукачев Н. В., Maslennikov D., Sosorev A. et al., The Journal of Physical Chemistry Letters 2019 Vol. 10 No. 12 P. 3232–3239
Conformational space of polyphenylenevinylene oligomers is systematically investigated computationally at energies relevant for room temperature dynamics in a solvent and in a solid state. Our calculations show that optimal oligomer structures are essentially planar. However, lack of a deep minimum at the planar geometry allows for large molecular deformations even at very low temperatures. At ...
Added: October 14, 2026
Тукачев Н. В., Akkuratov A., Kuznetsov I. et al., Synthetic Metals 2020 Vol. 259 Article 116231
Four new conjugated polymers based on benzodithiophene, thiophene and 2,1,3-benzothiadiazole or 5,6-difluoro-2,1,3-benzothiadiazole were synthesized and investigated as absorber materials for organic photovoltaics. The effect of (bi)thiophene π-spacers and fluorine substitution on the physicochemical and optoelectronic properties of the polymers was revealed and correlations were drawn with their electrical characteristics in organic solar cells. In particular, ...
Added: October 14, 2026
Тукачев Н. В., Nuraliev M., Parashchuk O. et al., Journal of Chemical Physics 2020 Vol. 153 No. 17 Article 174303
Electron–phonon interaction strongly affects and often limits charge transport in organic semiconductors (OSs). However, approaches to its experimental probing are still in their infancy. In this study, we probe the local electron–phonon interaction (quantified by the charge-transfer reorganization energy) in small-molecule OSs by means of Raman spectroscopy. Applying density functional theory calculations to four series ...
Added: October 14, 2026
Тукачев Н. В., Klimovich I., Prudnov F. et al., Dyes and Pigments 2021 Vol. 185 Article 108899
A series of ten conjugated polymers incorporating in their molecular frameworks extended DADAD building blocks with thiophene donor (D) and either benzotriazole, benzoxadiazole, benzothiadiazole, difluorobenzothiadiazole or quinoxaline acceptor (A) units were synthesized and characterized. The optoelectronic properties of new polymers were computed and experimentally investigated revealing a good relationship, which can guide further rational design ...
Added: October 14, 2026
Тукачев Н. В., Sosorev A., Parashchuk O. et al., Physical Chemistry Chemical Physics 2021 Vol. 23 No. 29 P. 15485–15491
Dynamic disorder manifested in fluctuations of charge transfer integrals considerably hinders charge transport in high-mobility organic semiconductors. Accordingly, strategies for suppression of the dynamic disorder are highly desirable. In this study, we suggest a novel promising strategy for suppression of dynamic disorder—tuning the molecular electrostatic potential. Specifically, we show that the intensities of the low-frequency ...
Added: October 14, 2026
Тукачев Н. В., González-Jiménez M., Ramakrishnan G. et al., Physical Chemistry Chemical Physics 2021 Vol. 23 No. 23 P. 13250–13260
Low-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA–protein recognition. However, understanding the vibrational basis of these mechanisms relies on theoretical models due to the lack of experimental evidence. Here we present the low-frequency vibrational spectra of G-quadruplexes (structures formed by four strands ...
Added: October 14, 2026
González-Jiménez M., Barnard T., Russell B. et al., Nature Communications 2023 Vol. 14 Article 215
A common feature of glasses is the “boson peak”, observed as an excess in the heat capacity over the crystal or as an additional peak in the terahertz vibrational spectrum. The microscopic origins of this peak are not well understood; the emergence of locally ordered structures has been put forward as a possible candidate. Here, ...
Added: October 14, 2026
Nikolaev G. A., Orlov O. V., Andreeva S. et al., Physical Review Applied 2026 Vol. 26 Article 014099
We report the electrical detection of the spin resonance with temporal resolution in a two-dimensional electron system. Spin resonance was excited by pulses of subterahertz radiation characterized by relatively short rise and fall times on the order of 10 ns and was observed as a resonant peak in the high-frequency conductivity of the two-dimensional channel. The ...
Added: July 31, 2026
Vyacheslav D. Neverov, Karabassov T., Andrey V. Krasavin et al., Research 2026 Vol. 9 Article 1087
Majorana zero modes (MZMs) localized in vortex cores of topological superconductors are widely regarded promising building blocks for fault-tolerant quantum computation. However, their unambiguous detection is hindered by the extremely small energy spacing separating them from conventional Caroli-de Gennes-Matricon states. Using a microscopic Bogoliubov-de Gennes approach, we demonstrate that nonmagnetic impurities, rather than suppressing, can ...
Added: February 17, 2026
A. N. Lyubchak, K. V. Shein, G.N. Goltsman et al., St. Petersburg Polytechnical University Journal: Physics and Mathematics 2024 Vol. 17 No. 3.2 P. 116–120
Terahertz (THz) integrated circuits is a promising platform to create low cost and efficient components for high-speed sixth-generation (6G) communication networks. One of the key components for this application is detectors and mixers integrated on THz silicon waveguide. Graphene, due to its unique and tunable properties such as zero band gap, high charge mobility and low electronic heat capacity, has ...
Added: November 5, 2024
Kravtsov M., Shilov A. L., Yang Y. et al., Nature Nanotechnology 2025 Vol. 20 No. 1 P. 51–56
Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the ...
Added: October 9, 2024
Svaytodukh S. S., Селиверстов С. В., Applied Physics Letters 2023 Vol. 124 No. 12
Added: May 12, 2024