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Multiorbital exchange Hamiltonians: Derivation and examples
Journal of Magnetism and Magnetic Materials. 2023. Vol. 587. Article 171315.
We present a detailed derivation of the effective Hamiltonian for a strongly correlated electron system involving
both orbital and spin degrees of freedom. This problem is relevant to a wide class of materials containing ions
with the orbitally degenerate ground state (Jahn–Teller ions). We treat in detail the case of double degenerate
orbitals, obtain the Kugel–Khomskii model, and then pass to a more general multiorbital case. Based on the
derived Hamiltonians, we analyze possible spin and orbital configurations, which can be rather nontrivial,
especially in the multiorbital case. A special emphasis is put on to a specific example of the square lattice of
Jahn–Teller ions typical of layered perovskites.
Degtyarev A., Bakhurin S., Yudin N., DSPA 2026 P. 1–6
This paper investigates one possible solution to the problem of self-interference cancellation (SIC) arising in the design of in-band full-duplex (IBFD) communication systems. Self-interference cancellation is performed in the digital domain using multilayer nonlinear models adapted via gradient-based optimization. The presence of local minima and saddle points during the adaptation of multilayer models limits the ...
Added: May 26, 2026
Qian X., Deng Y., Shchur L. et al., Physica A: Statistical Mechanics and its Applications 2026 Vol. 696 P. 1–13
We perform a Monte Carlo analysis of the Ising model on many three-dimensional lattices. By means of finite-size scaling we obtain the critical points and determine the scaling dimensions. As expected, the critical exponents agree with the three-dimensional Ising universality class for all models. The irrelevant field, as revealed by the correction-to-scaling amplitudes, appears to ...
Added: May 24, 2026
Melentiev P. N., Калмыков А. С., Гритченко А. С. et al., Успехи физических наук 2024 Т. 194 № 11 С. 1130–1145
Представлен краткий обзор достигнутого уровня оптических методов детектирования единичных молекул в биомедицинских приложениях. Показано, что регистрация флуоресценции единичных молекул красителей, ковалентно связанных с антителами (биомолекулами), совместно с использованием современных методов нанофотоники может быть применена для решения различных задач в биологии и медицине: визуализации биомолекул, токсинов, вирусных частиц, определения ультранизких концентраций аналитов напрямую во взятой пробе, ...
Added: May 21, 2026
Antsiferov P.S., Stepanov L.V., Matiukhin N. D., Review of Scientific Instruments 2025 Vol. 96 No. 12 Article 123506
The article presents the discharge plasma based source of extreme ultraviolet (EUV) radiation. The discharge circuit has been driven by means of stripe line storage with working voltage 10.5 kV. The main feature of the proposed source is that plasma electrons acquire the energy, necessary for the production of multiply charged ions with ionization potentials ...
Added: May 20, 2026
Анциферов П. С., Степанов Л. В., Матюхин Н. Д., Оптика и спектроскопия 2026 Т. 134 № 2 С. 214–218
Сообщено о разработке системы регистрации спектров на ПЗС-линейке для уникального ВУФ спектрометра, построенного на основе сферической дифракционной решетки с радиусом 6.65 m. Была использована линейка HAMAMATSU S11156-2048-02, которая устанавливалась по касательной к окружности Роуланда с возможностью механического перемещения для сканирования спектра. Были получены спектрограммы в диапазоне длин волн 2130-2270 Angstrem. Описана методика сшивки регистрируемых спектральных ...
Added: May 20, 2026
Shipilov F., Barnyakov A., Ivanov A. et al., / Series Physics "arxiv.org". 2026.
A fast simulation of the detector response is a vital task in high-energy physics (HEP). Traditional Monte-Carlo methods form the backbone of modern particle physics simulation software but are computationally expensive. We present a machine-learning-based approach to fast simulation of the Focusing Aerogel Ring Imaging Cherenkov (FARICH) detector response. Given a particle track and momentum, ...
Added: May 19, 2026
Malinovsky A. M., Пилипенко С. В., Mikhalchenko A. O. et al., Astronomy Reports 2026 Vol. 70 P. 1–6
Radiation from rotational transitions of CO molecules in distant galaxies creates a chaotic background with an intensity reaching 1000 Jy/sr at a wavelength of approximately 1 mm. This background will pose a serious problem, when measuring spectral distortions of the cosmic microwave background, in particular, the mu-distortion, which presumably has an intensity of less than ...
Added: May 19, 2026
Kaveev A. K., Fedorov V. V., Pavlov A. V. et al., Journal of Materials Chemistry C 2026 Vol. 14 No. 7 P. 2697–2705
Bismuth nanostructures represent a promising material platform for semiconductor nanooptoelectronics and colorimetry owing to the multi-colored light reflection and quantum confinement. In this work, we study the photoluminescent properties of bismuth nanostructures grown using molecular beam epitaxy on the planar CaF2/Si(111) surface. We demonstrate the different surface morphologies of Bi, ranging from planar films obtained ...
Added: May 19, 2026
Pavlova T., V.M. Shevlyuga (Шевлюга В. М., Applied Surface Science 2026 Vol. 736 P. 166813–166813
The objective of miniaturizing doped areas in silicon, with the ultimate goal of achieving atomic-precision doping, requires a fundamental understanding of the dopant incorporation process at the atomic level. We present a combined scanning tunneling microscopy (STM) and density functional theory (DFT) investigation of single phosphorus atom incorporation into the Si(100) surface. Phosphorus was supplied ...
Added: May 19, 2026
Pasternak D., Romshin A., Khmelnitsky Р. et al., Carbon 2026 Vol. 256 Article 121655
A single-photon source (SPS) is a key component required for quantum communication devices. We report the
discovery of bright diamond-based SPS created by nature. It is shown that narrow (≤2 nm) lines observed in the
500-800 nm range in photoluminescence (PL) spectra of the surface layer of untreated Yakut diamonds rich in
nitrogen and hydrogen are linked to ...
Added: May 19, 2026
A.M. Smirnov, Kurtina D. A., Saitov S. R. et al., Optical Materials: X 2026 Vol. 30 Article 100441
Chiral semiconductor nanostructures and nanoparticles are promising materials for applications in biological sensing, enantioselective separation, photonics, and spin-polarized devices. Here we performed a detailed analysis of optical properties of chiral CdSe nanoplatelets with thickness of 2 and 3 monolayers (ML) with Nacetyl-L-cysteine ligands. We studied the absorption spectra peculiarities, analyzed time-resolved photoluminescence and investigated circular ...
Added: May 18, 2026
Saitov S. R., Saidzhonov B. M., Vasiliev R. B. et al., Journal of Applied Physics 2026 Vol. 139 No. 18 Article 185702
This work presents a comprehensive investigation into the temperature-dependent thermally stimulated conductivity and photoconductivity of vacuum-annealed thin films based on core–shell CdSe/CdS nanoplatelets passivated with oleic acid ligands. Controlled thermal annealing under vacuum conditions leads to a substantial increase in both dark and photoinduced conductivity, which is primarily attributed to partial desorption of the ligands. ...
Added: May 18, 2026
Масютин Д. А., Moiseev E., Komarov S. et al., Письма в Журнал технической физики 2026 Т. 52 № 7 С. 27–30
Исследованы инжекционные полупроводниковые микролазеры с кольцевым резонатором радиусом 15 мкм с несимметричным расположением внутреннего отверстия резонатора. Показано, что асимметрия обеспечивает формирование в диаграмме направленности двух лепестков излучения, разориентированных на 50° относительно оси смещения внутреннего отверстия. Измеренная добротность резонаторов сопоставима с добротностью дисковых резонаторов и находится на уровне ∼ 10^6. ...
Added: May 18, 2026
Rathish S., Andrey S. Vasenko, Thazhathenair A. et al., The Journal of Physical Chemistry Letters 2026 Vol. 17 No. 18 P. 5386–5394
We demonstrate and rationalize the effect of Au nanoparticles (NPs) on the hierarchical g-C3N4/CeO2 heterojunction. g-C3N4/CeO2 decorated with monodispersed plasmonic Au NPs was synthesized. Detailed analyses showed that CeO2 nanocubes and monodispersed Au NPs were evenly distributed over the 2D g-C3N4 surface, forming a robust interface enriched with abundant active sites. The structure enabled efficient separation of photogenerated charge ...
Added: May 16, 2026
Paul R., Das A., Sharma N. et al., Colloids and Surfaces A: Physicochemical and Engineering Aspects 2026 Vol. 728 Article 138830
Niobium-doped TiO2 (Nb-TiO2), demonstrates dual functionality as an efficient photocatalyst for dye degradation and a promising photoelectrocatalyst for water oxidation. Nb incorporation via a facile hydrothermal method was confirmed by XRD (Rietveld refinement), XPS, TEM, FT-IR, Raman, and BET analyses, indicating successful lattice doping and structural modification. Photocatalytic dye degradation experiments were conducted using a model ...
Added: May 16, 2026
I. V. Kolokolov, V. V. Lebedev, Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 2026 Vol. 113 No. 5 Article 054117
We theoretically investigate the correlation functions of the phase of a light wave propagating through a
turbulent medium. We use an equation for the logarithm of a wave packet envelope, which includes a secondorder
nonlinear term. Based on this equation, we develop a diagrammatic technique to calculate corrections
to the correlation function obtained in the linear approximation. We ...
Added: May 15, 2026
Гущина В. А., / Series chemrxiv-2023-vpzhz-v2 "ChemRxiv". 2023.
All-inorganic perovskite CsPbBr3 and Cs4PbBr6 nanoparticles are being intensively studied due to their unique properties and wide range of applications; however, however, the nature of their optical properties is not yet fully understood due to the difficulty of synthesis of singlephase nanoparticles. In this article we describe the features of the synthesis of single-phase particles ...
Added: May 14, 2026
Гущина В. А., Mendeleev Communications 2025 Vol. 35 No. 2 P. 193–195
All-inorganic perovskite CsPbBr3 and Cs4PbBr6 nanoparticles are intensively studied for their unique optical properties, though synthesizing single-phase nanoparticles has posed challenges. Detailed synthesis method of CsPbBr3 and Cs4PbBr6 single-phase nanoparticles and their chemical and phase analysis are described. Distinctive optical characteristics, such as photoluminescence, optical band gap and the Urbach tail region, are revealed and explained within the current ...
Added: May 14, 2026
Zhu Q., Luo X., Shanenko A. et al., Chinese Journal of Physics 2025 Vol. 97 P. 768–776
Interference-induced surface superconductivity (SC), in which the surface critical temperature $T_{cs}$ is enhanced relative to the bulk critical temperature $T_{cb}$, has been predicted recently, sparking intensive studies of its properties within an attractive Hubbard model with $s$-wave pairing. However, a complete understanding of how the relative enhancement $\tau = (T_{cs} - T_{cb})/T_{cb}$ depends on microscopic ...
Added: September 15, 2025
Kagan M., Красавин А. В., Ikhsanov R. et al., Working papers by Cornell University. Series cond-mat.soft "arxiv.org" ( 2025
In the Review we discuss anomalous aspects of superconductivity (SC) and normal state, as
well as formation of inhomogeneous (droplet-like or cluster-like) states in electron systems with
attraction. We consider both the models with the retardation (Eliashberg mechanism of SC for
strong electron-phonon interaction in metallic hydrogen) and without retardation (but with local
onsite attraction). We concentrate on the ...
Added: August 27, 2025
Bogoslovskiy N. A., Петров П. В., Аверкиев Н. С., Physical Review B: Condensed Matter and Materials Physics 2024 No. 024436
We study the theoretical model of a ferromagnetic semiconductor as a system of randomly distributed
Ising spins with a long-range exchange interaction. Using the density-of-states approach, we
analytically obtain the magnetic susceptibility and heat capacity over a wide range of temperatures
and magnetic fields. It is shown that the finite system of spins in magnetic field less than ...
Added: July 9, 2025
Kovaleva N. N., Kusmartseva O. E., Kugel K., Journal of Physics: Conference Series 2024 Vol. 2769 Article 012013
Transition metal oxides incorporating Jahn-Teller (JT) ions Mn3+ (3d4) in manganites and Cu2+ (3d9) in cuprates exhibit outstanding magnetic and electronic properties, including colossal magnetoresistance (CMR) and high-temperature superconductivity (HTSC). The physics of these compounds is associated with the orbitally-degenerate electronic states of JT ions, leading to the linear electron-lattice interaction, complemented by the entirely electronic
superexchange (SE) interaction. Here, ...
Added: December 29, 2024
Kagan M., Ikhsanov R., Ковалев И. А. et al., Журнал экспериментальной и теоретической физики 2024 Т. 166 № 1 С. 89–97
Рассмотрена сверхпроводимость и неоднородные состояния в металлическом водороде и ряде электронных систем с притяжением, описываемых неоднородной (пространственно-разделенной) ферми-бозесмесью со сверхпроводящими кластерами или каплями параметра порядка в матрице расспаренных
нормальных состояний. Пространственно-разделенная ферми-бозе-смесь реализуется в сверхпроводящих
оксидах висмута BaKBiO3 . Капли параметра порядка могут возникать в тонких пленках «грязного»
(с большим количеством примесей) металла, описываемых двумерной моделью Хаббарда малой ...
Added: April 7, 2024
Жумагулов Я. В., Кашурников В. А., Красавин А. В. et al., Письма в Журнал экспериментальной и теоретической физики 2019 Т. 109 № 1-2 С. 48–53
Методом вариационного кластерного приближения рассчитана фазовая диаграмма двумерной двухорбитальной модели Хаббарда, широко используемой для описания высокотемпературных сверхпроводников на основе железа, в области электронного допирования. Получено, что сосуществование антиферромагнитной и сверхпроводящей фаз реализуется в широком диапазоне значений электронного допирования. В сверхпроводящей фазе параметр порядка имеет s±-симметрию. ...
Added: July 18, 2023