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Condens. Matter, Volume 10, Issue 2 (June 2025) – 16 articles

Cover Story (view full-size image): Asperomagnetism represents an intermediate state between ferromagnetism and spin glass behavior. Two categories of magnetic materials have been proposed to exhibit asperomagnetic order: those characterized by a broad distribution of exchange interactions that are predominantly positive, and those that possess strong random local anisotropy alongside primarily positive exchange interactions. Nevertheless, there has been a paucity of studies investigating this magnetic order since the 1980s. This study has successfully elucidated the static and dynamic properties of the asperomagnet (Ba,Na)(Zn,Mn)2As2 through the application of muon spin rotation (µSR) techniques for the first time. View this paper
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15 pages, 803 KiB  
Article
Field-Induced Ferroaxiality in Antiferromagnets with Magnetic Toroidal Quadrupole
by Satoru Hayami
Condens. Matter 2025, 10(2), 35; https://doi.org/10.3390/condmat10020035 - 14 Jun 2025
Viewed by 393
Abstract
Magnetic toroidal multipoles have recently emerged as key descriptors of unconventional cross-correlation phenomena in antiferromagnetic systems. Among them, the rank-2 magnetic toroidal quadrupole, which is characterized as a time-reversal-odd polar tensor, has been theoretically associated with a variety of cross-correlation phenomena arising from [...] Read more.
Magnetic toroidal multipoles have recently emerged as key descriptors of unconventional cross-correlation phenomena in antiferromagnetic systems. Among them, the rank-2 magnetic toroidal quadrupole, which is characterized as a time-reversal-odd polar tensor, has been theoretically associated with a variety of cross-correlation phenomena arising from the time-reversal symmetry breaking. In this study, we investigate the interplay between magnetic toroidal quadrupoles and electric toroidal dipoles in antiferromagnets, with a particular focus on magnetic field-induced ferroaxiality. Through symmetry analysis and microscopic model calculations, we demonstrate that ferroaxiality can be induced by an external magnetic field, depending on both the field direction and the type of the magnetic toroidal quadrupole. We classify all magnetic point groups that possess magnetic toroidal quadrupoles and identify various candidate materials based on the MAGNDATA database. Our findings reveal a route to coupling spin and lattice degrees of freedom via toroidal multipoles. Full article
(This article belongs to the Section Magnetism)
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8 pages, 227 KiB  
Perspective
The Standard Model of Particle Physics and What Lies Beyond: A View from the Bridge
by Pran Nath
Condens. Matter 2025, 10(2), 34; https://doi.org/10.3390/condmat10020034 - 13 Jun 2025
Viewed by 282
Abstract
The standard models of particle physics and of cosmology have been enormously successful in correlating a large amount of data. However, there are missing pieces and we are still far from what the ultimate model may look like. We give a broad perspective [...] Read more.
The standard models of particle physics and of cosmology have been enormously successful in correlating a large amount of data. However, there are missing pieces and we are still far from what the ultimate model may look like. We give a broad perspective of both the achievements and of the missing pieces and discuss what may lie beyond. Full article
8 pages, 2029 KiB  
Article
Mott Law exp(T0/T)1/4 and Scaling Properties of the Oxygen-Deficient Tenorite CuO0.75
by Danijel Djurek, Mladen Prester, Djuro Drobac, Vilko Mandić and Damir Pajić
Condens. Matter 2025, 10(2), 33; https://doi.org/10.3390/condmat10020033 - 11 Jun 2025
Viewed by 374
Abstract
The novel sub-stoichiometric copper oxide CuO0.75 was prepared via the slow oxidation of Cu2O. This compound retains the original crystallographic structure of tenorite CuO, despite the considerable presence of disordered oxygen vacancies. CuO0.75 resembles the mixed valence oxide Cu [...] Read more.
The novel sub-stoichiometric copper oxide CuO0.75 was prepared via the slow oxidation of Cu2O. This compound retains the original crystallographic structure of tenorite CuO, despite the considerable presence of disordered oxygen vacancies. CuO0.75 resembles the mixed valence oxide Cu2+/Cu1+, while the unit cell contains one oxygen vacancy. Performance-wise, the electric resistivity and magnetic susceptibility data follow the Anderson–Mott localization theories. The exponential localization decay length was found to be α−1 = 2.1 nm, in line with modern scaling research. Via cooling, magnetic double-exchange interaction, mediated by oxygen, results in Zener conductivity at T~122 K, which is followed by antiferromagnetic transition at T~51 K. The obtained results indicate that the CuO0.75 compound can be perceived as a showcase material for the demonstration of a new class of high-performance magnetic materials. Full article
(This article belongs to the Section Physics of Materials)
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11 pages, 232 KiB  
Review
Antimatter Research at the CERN Antiproton Decelerator: Legacy of Guido Barbiellini Amidei
by Rafael Ferragut
Condens. Matter 2025, 10(2), 32; https://doi.org/10.3390/condmat10020032 - 3 Jun 2025
Viewed by 740
Abstract
This work reviews the current research directions pursued by collaborations at CERN’s Antiproton Decelerator (AD), with an outlook on future perspectives and challenges in the field. The advancement of precision studies on antimatter builds upon foundational contributions by pioneering researchers, such as Guido [...] Read more.
This work reviews the current research directions pursued by collaborations at CERN’s Antiproton Decelerator (AD), with an outlook on future perspectives and challenges in the field. The advancement of precision studies on antimatter builds upon foundational contributions by pioneering researchers, such as Guido Barbiellini Amidei, whose early work on antimatter detection and instrumentation has profoundly influenced the design and methodologies of contemporary experiments at the AD and beyond. This review underscores the lasting impact of these early innovations on ongoing investigations into fundamental symmetries and interactions involving antimatter. Full article
14 pages, 10385 KiB  
Article
Correlation Between Structure, Microstructure, and Magnetic Properties of AlCoCrFeNi High-Entropy Alloy
by Renee Joselin Sáenz-Hernández, Carlos Roberto Santillán-Rodríguez, Jesús Salvador Uribe-Chavira, José Andrés Matutes-Aquino and María Cristina Grijalva-Castillo
Condens. Matter 2025, 10(2), 31; https://doi.org/10.3390/condmat10020031 - 27 May 2025
Viewed by 582
Abstract
This study explores the crystal structure, microstructure and magnetic phase evolution of the AlCoCrFeNi high-entropy alloy (HEA), highlighting its potential for applications requiring tailored magnetic properties across diverse temperatures. Electron microscopy and X-ray diffraction revealed that the as-cast alloy’s microstructure comprises equiaxed grains [...] Read more.
This study explores the crystal structure, microstructure and magnetic phase evolution of the AlCoCrFeNi high-entropy alloy (HEA), highlighting its potential for applications requiring tailored magnetic properties across diverse temperatures. Electron microscopy and X-ray diffraction revealed that the as-cast alloy’s microstructure comprises equiaxed grains with branching dendrites, showing compositional variations between interdendritic regions enriched in Al and Ni. Temperature-induced phase transformations were observed above room temperature, transitioning from body centered cubic (BCC) phases (A2 and B2) to a predominant FCC phase at higher temperatures, followed by recrystallization of the A2 phase upon cooling. Magnetization measurements showed a drop near 380 K, suggesting the Curie temperature of BCC phases, a peak at 830 K attributed to optimal magnetic alignment in the FCC phase, and a sharp decline at 950 K marking the transition to a paramagnetic state. Magnetic moment calculations provided insights into magnetic alignment dynamics, while low-temperature analysis highlighted the alloy’s magnetically soft nature, dominated by ferromagnetic contributions from the A2 phase. These findings underscore the strong interdependence of microstructural features and magnetic behavior, offering a foundation for optimizing HEAs for temperature-sensitive scientific and industrial applications. Full article
(This article belongs to the Section Magnetism)
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11 pages, 3191 KiB  
Article
Magnetic Evolution of Carrier Doping and Spin Dynamics in Diluted Magnetic Semiconductors (Ba,Na)(Zn,Mn)2As2
by Guoqiang Zhao, Yipeng Cai, Kenji M. Kojima, Qi Sheng, James Beare, Graeme Luke, Xiang Li, Yi Peng, Timothy Ziman, Kan Zhao, Zheng Deng, Xiancheng Wang, Yongqing Li, Gang Su, Sadamichi Maekawa, Bo Gu, Yasutomo J. Uemura and Changqing Jin
Condens. Matter 2025, 10(2), 30; https://doi.org/10.3390/condmat10020030 - 15 May 2025
Cited by 2 | Viewed by 658
Abstract
The investigation of novel diluted magnetic semiconductors (DMSs) provides a promising platform for studying magnetism and transport characteristics, with significant implications for spintronics. DMSs based on BaZn2As2 are particularly noteworthy due to their high Curie temperature (TC) [...] Read more.
The investigation of novel diluted magnetic semiconductors (DMSs) provides a promising platform for studying magnetism and transport characteristics, with significant implications for spintronics. DMSs based on BaZn2As2 are particularly noteworthy due to their high Curie temperature (TC) of 260 K, diverse magnetic states, and potential for multilayer heterojunctions. This study investigates the magnetic evolution of carrier doping and spin dynamics in the asperomagnet (Ba,Na)(Zn,Mn)2As2, utilizing a combination of magnetization measurements, ac susceptibility, and muon spin rotation (µSR). Key findings include the following: (1) lower transition temperatures and coercive forces in (Ba,Na)(Zn,Mn)2As2 compared to the ferromagnet (Ba,K)(Zn,Mn)2As2; (2) a dynamic fluctuation peak around the transition temperature observed in both the ac susceptibility and longitudinal field (LF) µSR; and (3) the coexistence of static and dynamic states at low temperatures, exhibiting spin-glass-like characteristics. This study, to the best of our knowledge, may represent the first investigation of asperomagnetic order utilizing µSR techniques. It enhances the understanding of magnetic interactions in BaZn2As2-based systems and provides valuable insights into the exploration of high TC DMSs. Full article
(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)
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15 pages, 4030 KiB  
Article
The Defect Charge Effect on Magnetic Anisotropy Energy and Dzyaloshinskii–Moriya Interaction of the I Vacancy and 3d Transition Metal Co-Doped Monolayer CrI3
by Guangtian Ji, Qingqing Yang, Kun Zhang, Jueming Yang, Guixian Ge and Wentao Wang
Condens. Matter 2025, 10(2), 29; https://doi.org/10.3390/condmat10020029 - 14 May 2025
Viewed by 1130
Abstract
Recently, significant effort has been devoted to enhancing magnetic anisotropy energy (MAE) and the Dzyaloshinskii–Moriya interaction (DMI) in two-dimensional (2D) ferromagnetic materials through various tuning approaches. Among these methods, defect engineering is one of the most effective strategies. However, the influence of these [...] Read more.
Recently, significant effort has been devoted to enhancing magnetic anisotropy energy (MAE) and the Dzyaloshinskii–Moriya interaction (DMI) in two-dimensional (2D) ferromagnetic materials through various tuning approaches. Among these methods, defect engineering is one of the most effective strategies. However, the influence of these charged defects on the MAE and DMI is unclear. Therefore, we systematically investigate the defect effect on the MAE and DMI of I vacancy-doped (vI-CrI3), 3d-transition-metal-doped (TM = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) (3d-TMi@CrI3), and vI-TM co-doped (3d-TMi@vI-CrI3) monolayer CrI3 using first-principles calculations. Our results indicate that Cr-rich conditions can promote the defect formation of vI-CrI3, 3d-TMi@CrI3, and 3d-TMi@vI-CrI3 systems and demonstrate that 49 types of charged systems are stable. Among these systems, the Cui@vI-CrI3 in the +1 charge state (Cui@vI-CrI3) system has a smaller defect formation energy, exhibiting a large MAE exceeding 30 meV, and the ratio (D/J) of the antisymmetric magnetic exchange parameter (D) to the Heisenberg exchange parameter (J) reaches 1.04. The large MAE originates from the transition from single-ion anisotropy (SIA) to covalent interaction anisotropy (CIA) due to the coupling variation between the py and px orbitals of I atoms near the Fermi level caused by charge states. The enhancement of the DMI is due to the electrostatic potential differences between the I-top and I-bottom layers, which are conducive to forming stable chiral spin textures. This study provides insight into the defect charge state modulating the magnetism of 2D magnetic materials. Full article
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8 pages, 1555 KiB  
Article
Effect of Annealing Time of GaN Buffer Layer on Curvature and Wavelength Uniformity of Epitaxial Wafer
by Huanyou Wang, Guangqi Xie and Yingying Zhan
Condens. Matter 2025, 10(2), 28; https://doi.org/10.3390/condmat10020028 - 1 May 2025
Viewed by 465
Abstract
In this study, the curvature changes of an unintentionally doped GaN end and third quantum well were observed in situ when the annealing times of a GaN buffer layer were 40 s, 50 s and 55 s, respectively. When the annealing time was [...] Read more.
In this study, the curvature changes of an unintentionally doped GaN end and third quantum well were observed in situ when the annealing times of a GaN buffer layer were 40 s, 50 s and 55 s, respectively. When the annealing time was increased from 40 s to 50 s, the concave curvature of the unintentionally doped GaN end and the third quantum well became smaller. When the annealing time was increased to 55 s, there was no significant change in curvature. These curvature changes are related to the relaxation of the stress in the epitaxial wafer with different annealing times. With the increase in buffer annealing time, the compressive stress and warpage decreased gradually, and the photoluminescence wavelength of the sample became longer. Meanwhile, the standard deviation yield of the dominant wavelength was increased by 5.46%, and the wavelength yield was increased by 19.45% when the annealing time was changed from 40 s to 50 s. Full article
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13 pages, 751 KiB  
Article
Effect of t2g-Correlations and Doping in CrSBr Ferromagnetic Semiconductor
by Luis Craco and Sabrina Silva Carara
Condens. Matter 2025, 10(2), 27; https://doi.org/10.3390/condmat10020027 - 28 Apr 2025
Viewed by 952
Abstract
We perform a comprehensive analysis of the correlated electronic structure reconstruction of the ferromagnetic CrSBr van der Waals (vdW) bulk crystal. Using generalized gradient approximation combined with dynamical mean-field theory, we show the minor role played by multi-orbital electron–electron interactions in semiconducting CrSBr. [...] Read more.
We perform a comprehensive analysis of the correlated electronic structure reconstruction of the ferromagnetic CrSBr van der Waals (vdW) bulk crystal. Using generalized gradient approximation combined with dynamical mean-field theory, we show the minor role played by multi-orbital electron–electron interactions in semiconducting CrSBr. Our study is relevant to understanding the electronic structure within the Cr3+ oxidation state with strongly spin-polarized t2g orbitals and should be applicable to other ferromagnetic vdW materials from bulk down to the low-dimensional limit. This work is relevant for understanding orbital and spin selectivity and its link to the memristor current–voltage characteristic of CrSBr for future neuromorphic computing. Full article
(This article belongs to the Section Condensed Matter Theory)
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18 pages, 23429 KiB  
Article
Synthesis of PTh/PEDOT Films into FTO Substrate by Electrodeposition, for Energy Storage Systems
by Daniel Alejandro Vázquez-Loredo, Ulises Páramo-García, Luis Alejandro Macclesh Del Pino-Pérez, Nohra Violeta Gallardo-Rivas, Ricardo García-Alamilla and Diana Lucia Campa-Guevara
Condens. Matter 2025, 10(2), 26; https://doi.org/10.3390/condmat10020026 - 27 Apr 2025
Viewed by 993
Abstract
Thin films of monomeric species polythiophene (PTh), poly-(3,4-ethylenedioxythiophene) (PEDOT), and the copolymer PTh/PEDOT were prepared through electropolymerization and deposited above fluorine-doped tin oxide (FTO) substrates. The functional groups of the monomeric species (PTh, PEDOT) and polymeric species (PTh/PEDOT) were characterized by Fourier-transform infrared [...] Read more.
Thin films of monomeric species polythiophene (PTh), poly-(3,4-ethylenedioxythiophene) (PEDOT), and the copolymer PTh/PEDOT were prepared through electropolymerization and deposited above fluorine-doped tin oxide (FTO) substrates. The functional groups of the monomeric species (PTh, PEDOT) and polymeric species (PTh/PEDOT) were characterized by Fourier-transform infrared spectroscopy, while morphological properties were evaluated using scanning electron microscopy, optical microscopy, and atomic force microscopy. The analysis showed that monomers films exhibited less material deposition; otherwise, the copolymer PTh/PEDOT showed better deposition on substrate. In addition, the electrochemical characterization showed that the materials that resulted from copolymerization presented an improvement in electrochemical properties relating to monomer properties. The effect of overoxidation of the monomers applied during the electropolymerization process is also known. Full article
(This article belongs to the Section Surface and Interfaces)
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3 pages, 145 KiB  
Editorial
Novel Radiation Facilities Based on Plasma Acceleration: The Future of Free Electron Lasers
by Marcello Coreno, Massimo Ferrario, Augusto Marcelli and Francesco Stellato
Condens. Matter 2025, 10(2), 25; https://doi.org/10.3390/condmat10020025 - 27 Apr 2025
Viewed by 274
Abstract
Exploiting acceleration gradients that are up to three orders of magnitude higher than those achievable using conventional radiofrequency-based devices, plasma-based devices promise a revolution in particle acceleration, enabling particles to reach high energies over much shorter distances than existing accelerators [...] Full article
3 pages, 123 KiB  
Editorial
In-Depth Experimental and Computational Studies on Rechargeable Battery Materials
by Jan Kuriplach and Rolando Saniz
Condens. Matter 2025, 10(2), 24; https://doi.org/10.3390/condmat10020024 - 25 Apr 2025
Viewed by 257
Abstract
Judging by the number of downloads and citations, the topics covered by the Special Issue “Rechargeable Batteries Studied Using Advanced Spectroscopic and Computational Techniques I” [...] Full article
8 pages, 512 KiB  
Article
Energy Structure of Yb3+-Yb3+ Paired Center in LiNbO3 Crystal
by Gagik Demirkhanyan, Narine Babajanyan, Ninel Kokanyan, Michel Aillerie, Marco Bazzan and Edvard Kokanyan
Condens. Matter 2025, 10(2), 23; https://doi.org/10.3390/condmat10020023 - 25 Apr 2025
Viewed by 468
Abstract
Within the framework of Dexter’s theory, we calculate the energies of the Stark levels of Yb3+-Yb3+ paired centers in lithium niobate doped with Yb3+ ions (LiNbO3:Yb3+) crystal, considering the interaction of optical electrons of ytterbium [...] Read more.
Within the framework of Dexter’s theory, we calculate the energies of the Stark levels of Yb3+-Yb3+ paired centers in lithium niobate doped with Yb3+ ions (LiNbO3:Yb3+) crystal, considering the interaction of optical electrons of ytterbium ions forming the paired center. The calculated Stark level energies are shown to correspond well with the observed cooperative luminescence wavelengths. Full article
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24 pages, 3710 KiB  
Review
The Laser Powder Bed Fusion of Nd2Fe14B Permanent Magnets: The State of the Art
by Ivan Pelevin, Maria Lyange, Leonid Fedorenko, Stanislav Chernyshikhin and Irina Tereshina
Condens. Matter 2025, 10(2), 22; https://doi.org/10.3390/condmat10020022 - 24 Apr 2025
Viewed by 1702
Abstract
In recent years, significant effort was made to make the 3D printing of fully dense rare-earth permanent magnets a reality. Since suitable Nd2Fe14B-based initial powder material became available, additive manufacturing implementation spread widely, which led to many studies being [...] Read more.
In recent years, significant effort was made to make the 3D printing of fully dense rare-earth permanent magnets a reality. Since suitable Nd2Fe14B-based initial powder material became available, additive manufacturing implementation spread widely, which led to many studies being focused on using this material in 3D printing. This study shows the principal possibilities of the synthesis of Nd-Fe-B magnets by means of the laser powder bed fusion technique; moreover, this study shows significant progress in increasing their magnetic properties. This progress was made possible by different approaches, such as 3D-printing process optimization, the addition of a second phase (a low-melting eutectic) into the initial powder, the tuning of the main phase’s composition, and exploring different scanning strategies. However, the current level of material magnetic properties obtained via laser powder bed fusion is still far from that of magnets produced by using conventional powder metallurgy methods. The present review aims to capture the current state-of-the-art trials and highlight the main challenges. Full article
(This article belongs to the Section Magnetism)
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29 pages, 10332 KiB  
Review
Basic Aspects of Ferroelectricity Induced by Noncollinear Alignment of Spins
by I. V. Solovyev
Condens. Matter 2025, 10(2), 21; https://doi.org/10.3390/condmat10020021 - 11 Apr 2025
Viewed by 799
Abstract
Basic principles of ferroelectric activity induced by the noncollinear alignment of spins are reviewed. There is a fundamental reason why the inversion symmetry can be broken by certain magnetic order. This situation occurs when the magnetic order simultaneously involves ferromagnetic (F) [...] Read more.
Basic principles of ferroelectric activity induced by the noncollinear alignment of spins are reviewed. There is a fundamental reason why the inversion symmetry can be broken by certain magnetic order. This situation occurs when the magnetic order simultaneously involves ferromagnetic (F) and antiferromagnetic (A) counterparts, transforming under the spatial inversion I and time reversal T as IF=F and ITA=A, respectively. The incompatibility of these two conditions results in breaking the inversion symmetry, which manifests itself in the electric polarization P. The noncollinear alignment of spins is one of examples of such coexistence of F and A. This coexistence principle imposes a constraint on possible dependencies of P on the directions of spins, which can include only “antisymmetric coupling” in the bond, Pij·[ei×ej], and “single-ion anisotropy”, ei· Π ei. Microscopically, Pij can be evaluated in the framework of superexchange theory. For the single Kramers doublet, this theory yields Pijrij0, where rij0 is the spin-dependent part of the position operator induced by the relativistic spin-orbit coupling. rij0 remains invariant under spatial inversion, providing the microscopic reason why noncollinear alignment of spins can induce P even in centrosymmetric crystals. The symmetry properties of rij0 can be rationalized from the viewpoint of symmetry of Kramers states. Particularly, the commonly used Katsura–Nagaosa–Balatsky (KNB) rule Pϵji×[ei×ej] (ϵji being the direction of the bond ij) can be justified only for relatively high symmetry of the bonds. The single-ion anisotropy vanishes for the spin 12 or if magnetic ions are located in inversion centers, thus severely restricting the applicability of this microscopic mechanism. The properties of multiferroic materials are reconsidered from the viewpoint of these principles. A particular attention is paid to complications caused by possible deviations from the KNB rule. Full article
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14 pages, 991 KiB  
Review
Emergent Magnetic Monopoles in Quantum Matter
by Maria Cristina Diamantini
Condens. Matter 2025, 10(2), 20; https://doi.org/10.3390/condmat10020020 - 1 Apr 2025
Viewed by 1062
Abstract
Magnetic monopoles, though elusive as elementary particles, emerge as quantum excitations in granular quantum materials. Under certain conditions, they can undergo Bose condensation, leading to the formation of a novel state of matter known as the superinsulator. In this state, charge carriers, Cooper [...] Read more.
Magnetic monopoles, though elusive as elementary particles, emerge as quantum excitations in granular quantum materials. Under certain conditions, they can undergo Bose condensation, leading to the formation of a novel state of matter known as the superinsulator. In this state, charge carriers, Cooper pairs and anti-Cooper pairs, are bound together by an electric flux string, forming neutral electric pions. This confinement mechanism results in an infinite resistance that persists even at finite temperatures. Superinsulators behave, thus, as dual superconductors. Full article
(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)
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