Condensed Matter

16 pages, 509 KiB

Open AccessFeature PaperArticle

Single-Defect-Induced Peculiarities in Inverse Faraday-Based Switching of Superconducting Current-Carrying States near a Critical Temperature

by Mihail D. Croitoru and Alexander I. Buzdin

Condens. Matter 2024, 9(4), 48; https://doi.org/10.3390/condmat9040048 - 12 Nov 2024

Abstract

The Inverse Faraday Effect (IFE) is a phenomenon that enables non-thermal magnetization in various types of materials through the interaction with circularly polarized light. This study investigates the impact of single defects on the ability of circularly polarized radiation to switch between distinct [...] Read more.

The Inverse Faraday Effect (IFE) is a phenomenon that enables non-thermal magnetization in various types of materials through the interaction with circularly polarized light. This study investigates the impact of single defects on the ability of circularly polarized radiation to switch between distinct superconducting current states, when the magnetic flux through a superconducting ring equals half the quantum flux,

Φ_{0} / 2

. Using both analytical methods within the standard Ginzburg–Landau theory and numerical simulations based on the stochastic time-dependent Ginzburg–Landau approach, we demonstrate that while circularly polarized light can effectively switch between current-carrying superconducting states, the presence of a single defect significantly affects this switching mechanism. We establish critical temperature conditions above which the switching effect completely disappears, offering insights into the limitations imposed by a single defect on the dynamics of light-induced IFE-based magnetization in superconductors. Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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7 pages, 2589 KiB

Open AccessArticle

Electromagnetic Modeling of Superconducting Bulks in Applied Time-Varying Magnetic Field

by Hocine Menana

Condens. Matter 2024, 9(4), 47; https://doi.org/10.3390/condmat9040047 - 9 Nov 2024

Abstract

An integrodifferential model formulated in terms of the electric vector potential is developed for the 3D numerical modeling of the electromagnetic field in superconducting bulks, for AC losses evaluation. The Newton Raphson method is applied to accelerate the convergence. The model is validated [...] Read more.

An integrodifferential model formulated in terms of the electric vector potential is developed for the 3D numerical modeling of the electromagnetic field in superconducting bulks, for AC losses evaluation. The Newton Raphson method is applied to accelerate the convergence. The model is validated on a benchmark. The comparison results show the accuracy of the model and its performances in terms of computation time compared to classical approaches. Full article

(This article belongs to the Special Issue Selected Papers from the International Conference on Quantum Materials and Technologies (ICQMT2024))

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16 pages, 3203 KiB

Open AccessReview

Readout Methods to Enhance the Performance of Luminescence Thermometers

by Miroslav D. Dramićanin, Abdullah N. Alodhayb and Aleksandar Ćirić

Condens. Matter 2024, 9(4), 46; https://doi.org/10.3390/condmat9040046 - 9 Nov 2024

Abstract

Over the past three decades, luminescence thermometry has gained significant attention among researchers and practitioners. The method has progressed in terms of utilizing temperature-sensitive luminescent materials, obtaining temperature read-outs from luminescence, developing applications, and improving performance. This paper reviews and critically analyzes routes [...] Read more.

Over the past three decades, luminescence thermometry has gained significant attention among researchers and practitioners. The method has progressed in terms of utilizing temperature-sensitive luminescent materials, obtaining temperature read-outs from luminescence, developing applications, and improving performance. This paper reviews and critically analyzes routes for improving luminescence thermometry performance, in particular the sensitivity, accuracy, and precision of the method. These include the use of highly temperature-sensitive probes, temperature read-outs from luminescence with improved sensitivity, multiparameter temperature-reading methods, the applications of principal component analysis and artificial neural networks, and sensor fusion. Full article

(This article belongs to the Section Spectroscopy and Imaging in Condensed Matter)

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63 pages, 23768 KiB

Open AccessReview

Magnetization Plateaus by the Field-Induced Partitioning of Spin Lattices

by Myung-Hwan Whangbo, Hyun-Joo Koo, Reinhard K. Kremer and Alexander N. Vasiliev

Condens. Matter 2024, 9(4), 45; https://doi.org/10.3390/condmat9040045 - 4 Nov 2024

Abstract

To search for a conceptual picture describing the magnetization plateau phenomenon, we surveyed the crystal structures and the spin lattices of those magnets exhibiting plateaus in their magnetization vs. magnetic field curves by probing the three questions: (a) why only certain magnets exhibit [...] Read more.

To search for a conceptual picture describing the magnetization plateau phenomenon, we surveyed the crystal structures and the spin lattices of those magnets exhibiting plateaus in their magnetization vs. magnetic field curves by probing the three questions: (a) why only certain magnets exhibit magnetization plateaus, (b) why there occur several different types of magnetization plateaus, and (c) what controls the widths of magnetization plateaus. We show that the answers to these questions lie in how the magnets under field absorb Zeeman energy, hence changing their magnetic structures. The magnetic structure of a magnet insulator is commonly described in terms of its spin lattice, which requires the determination of the spin exchanges’ nonnegligible strengths between the magnetic ions. Our work strongly suggests that a magnet under the magnetic field partitions its spin lattice into antiferromagnetic (AFM) or ferrimagnetic fragments by breaking its weak magnetic bonds. Our supposition of the field-induced partitioning of spin lattices into magnetic fragments is supported by the anisotropic magnetization plateaus of Ising magnets and by the highly anisotropic width of the 1/3-magnetization plateau in azurite. The answers to the three questions (a)–(c) emerge naturally by analyzing how these fragments are formed under the magnetic field. Full article

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13 pages, 1122 KiB

Open AccessFeature PaperArticle

Simple Model for T_c and Pairing Symmetry Changes in Sr₂RuO₄ Under (100) Uniaxial Strain

by Macauley Curtis, Martin Gradhand and James F. Annett

Condens. Matter 2024, 9(4), 44; https://doi.org/10.3390/condmat9040044 - 1 Nov 2024

Abstract

Uniaxial strain in the (100) direction has the effect of increasing the superconducting

T_{c}

in Sr₂RuO₄ from

1.5

K to over 3 K. The enhanced

T_{c}

corresponds to a Lifshitz transition in the Fermi surface topology of this [...] Read more.

Uniaxial strain in the (100) direction has the effect of increasing the superconducting

T_{c}

in Sr₂RuO₄ from

1.5

K to over 3 K. The enhanced

T_{c}

corresponds to a Lifshitz transition in the Fermi surface topology of this unconventional superconductor. We model this using a simple two-dimensional one-band model for the

γ

sheet of the Fermi surface. This reproduces the experimental

T_{c}

results well if we assume a

d_{x^{2} - y^{2}}

singlet pairing state. On the other hand, the triplet state

p_{x} + i p_{y}

does not show any distinct peaks in

T_{c}

associated with the Lifshitz transition. A mixed symmetry state pairing of the form

d + i g

can both describe the

T_{c}

changes and show a distinct transition temperature for time-reversal symmetry breaking (TRSB). Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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10 pages, 2113 KiB

Open AccessFeature PaperArticle

Kondo Versus Fano in Superconducting Artificial High-Tc Heterostructures

by Gaetano Campi, Gennady Logvenov, Sergio Caprara, Antonio Valletta and Antonio Bianconi

Condens. Matter 2024, 9(4), 43; https://doi.org/10.3390/condmat9040043 - 31 Oct 2024

Abstract

Recently, the quest for high-Tc superconductors has evolved from the trial-and-error methodology to the growth of nanostructured artificial high-Tc superlattices (AHTSs) with tailor-made superconducting functional properties by quantum design. Here, we report the growth by molecular beam epitaxy (MBE) of a superlattice of [...] Read more.

Recently, the quest for high-Tc superconductors has evolved from the trial-and-error methodology to the growth of nanostructured artificial high-Tc superlattices (AHTSs) with tailor-made superconducting functional properties by quantum design. Here, we report the growth by molecular beam epitaxy (MBE) of a superlattice of Mott insulator metal interfaces (MIMIs) made of nanoscale superconducting layers of quantum confined-space charge in the Mott insulator La₂CuO₄ (LCO), with thickness L intercalated by normal metal La_1.55Sr_0.45CuO₄ (LSCO) with period d. The critical temperature shows the superconducting dome with Tc as a function of the geometrical parameter L/d showing the maximum at the magic ratio L/d = 2/3 where the Fano–Feshbach resonance enhances the superconducting critical temperature. The normal state transport data of the samples at the top of the superconducting dome exhibit Planckian T-linear resistivity. For L/d > 2/3 and L/d < 2/3, the heterostructures show a resistance following Kondo universal scaling predicted by the numerical renormalization group theory for MIMI nanoscale heterostructures. We show that the Kondo temperature, T_K, and the Kondo scattering amplitude, R_0K, vanish at L/d = 2/3, while T_K and R_0K increase at both sides of the superconducting dome, indicating that the T-linear resistance regime competes with the Kondo proximity effect in the normal phase of MIMIs. Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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11 pages, 418 KiB

Open AccessArticle

Two-Band Electronic Reconstruction Induced via Correlation and CDW Order Effects

by L. Craco

Condens. Matter 2024, 9(4), 42; https://doi.org/10.3390/condmat9040042 - 30 Oct 2024

Abstract

The emergence of a charge density wave (CDW) in transition-metal dichalcogenides opens up a route to charge order, followed by superconductivity at low temperatures. A key question here concerns how many particle electron–electron interations govern the low-energy electronic structure in the normal and [...] Read more.

The emergence of a charge density wave (CDW) in transition-metal dichalcogenides opens up a route to charge order, followed by superconductivity at low temperatures. A key question here concerns how many particle electron–electron interations govern the low-energy electronic structure in the normal and CDW states. Using dynamical mean-field theory, we explore the many-body properties of an extended, two-band Hubbard model applicable to

2 H

-TaSe₂. We reveal the electronic structure reconstruction in the normal and CDW states driven by two-band dynamical correlations. Our results demonstrate a remarkable renormalization of the Ta-

5 d

bands crossing the Fermi level, showing a continuous reduction in the CDW gap up to an incomplete gapping, followed by a CDW to a CDW–Mott phase transition pertinent to strongly correlated transition-metal dichalcogenides. Full article

(This article belongs to the Section Condensed Matter Theory)

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10 pages, 546 KiB

Open AccessFeature PaperReview

Josephson Critical Currents and Related Effects in Ultracold Atomic Superfluid Sytems

by Verdiana Piselli, Leonardo Pisani and Giancarlo Calvanese Strinati

Condens. Matter 2024, 9(4), 41; https://doi.org/10.3390/condmat9040041 - 30 Oct 2024

Abstract

The Josephson and Proximity effects play a pivotal role in the design of superconducting devices for the implementation of quantum technology, ranging from the standard

A l

based to the more exotic twisted high-

T_{c}

junctions. Josephson critical currents have been recently [...] Read more.

The Josephson and Proximity effects play a pivotal role in the design of superconducting devices for the implementation of quantum technology, ranging from the standard

A l

based to the more exotic twisted high-

T_{c}

junctions. Josephson critical currents have been recently investigated also in ultracold atomic systems where a potential barrier acts as a weak link. The unifying feature of the above systems, apart from being superconducting/superfluid, is the presence of spatial inhomogeneity, a feature that has to be properly taken into account in any theoretical approach employed to investigate them. In this work, we review the novel (dubbed LPDA for Local Phase Density Approximation) approach based on a coarse graining of the Bogoliubov–de Gennes (BdG) equations. Non-local and local forms of this coarse graining were utilized when investigating Proximity and Josephson effects. Moreover, the LPDA approach was further developed to include pairing fluctuations at the level of the non-self-consistent t-matrix approximation. The resulting approach, dubbed mLPDA (

m o d i f i e d

LPDA), can be used whenever inhomegeneity and fluctuations effects simultaneously play an important role. Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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11 pages, 816 KiB

Open AccessArticle

Double-Q Checkerboard Bubble Crystal in Centrosymmetric Tetragonal Magnets

by Satoru Hayami

Condens. Matter 2024, 9(4), 40; https://doi.org/10.3390/condmat9040040 - 16 Oct 2024

Abstract

We report our numerical studies on the emergence of a double-Q checkerboard bubble crystal in centrosymmetric tetragonal magnets. The double-Q checkerboard bubble crystal is characterized by a fourfold-symmetric collinear spin configuration consisting of a superposition of two sinusoidal waves with the [...] Read more.

We report our numerical studies on the emergence of a double-Q checkerboard bubble crystal in centrosymmetric tetragonal magnets. The double-Q checkerboard bubble crystal is characterized by a fourfold-symmetric collinear spin configuration consisting of a superposition of two sinusoidal waves with the out-of-plane spin modulations along the [110] and [

\bar{1}

10] directions. The numerical calculations based on the simulated annealing for an effective spin model with the momentum-resolved easy-axis exchange interactions reveal that the double-Q checkerboard bubble crystal is energetically degenerate with the single-Q collinear state when the ordering wave vector lies on the quarter of the reciprocal lattice vector along the

⟨ 110 ⟩

direction. We show that such a degeneracy is lifted by considering the biquadratic interaction. We also find that the double-Q checkerboard bubble crystal turns into another double-Q state characterized by the in-plane spin modulations by increasing an external magnetic field. Full article

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18 pages, 4725 KiB

Open AccessCommunication

From Phonons to Domain Walls, the Central Peak and “Critical Slowing Down”

by Ekhard K. H. Salje and Annette Bussmann-Holder

Condens. Matter 2024, 9(4), 39; https://doi.org/10.3390/condmat9040039 - 1 Oct 2024

Abstract

We investigate perovskite oxides from different perspectives, namely their pseudo-harmonic dynamical properties, their dynamical properties when strong anharmonicity exists, and the intriguing functionalities arising from domain walls. Taking these viewpoints together yields a rather complex picture of this material class, which has not [...] Read more.

We investigate perovskite oxides from different perspectives, namely their pseudo-harmonic dynamical properties, their dynamical properties when strong anharmonicity exists, and the intriguing functionalities arising from domain walls. Taking these viewpoints together yields a rather complex picture of this material class, which has not been found in previous approaches. It opens pathways to novel applications and reveals the rich ground states beyond the fictitious belief in the ‘simplicity of perovskites and such structures’. Full article

(This article belongs to the Special Issue Complexity in Quantum Materials: In Honor of Prof. K.A. Muller)

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12 pages, 846 KiB

Open AccessFeature PaperArticle

Undamped Higgs Modes in Strongly Interacting Superconductors

by José Lorenzana and Götz Seibold

Condens. Matter 2024, 9(4), 38; https://doi.org/10.3390/condmat9040038 - 30 Sep 2024

Abstract

In superconductors, gauge

U (1)

symmetry is spontaneously broken. According to Goldstone’s theorem, this breaking of a continuous symmetry establishes the existence of the Bogoliubov phase mode while the gauge-invariant response also includes the amplitude fluctuations of the order parameter. The [...] Read more.

In superconductors, gauge

U (1)

symmetry is spontaneously broken. According to Goldstone’s theorem, this breaking of a continuous symmetry establishes the existence of the Bogoliubov phase mode while the gauge-invariant response also includes the amplitude fluctuations of the order parameter. The latter, which are also termed ‘Higgs’ modes in analogy with the standard model, appear at the energy of the spectral gap

2 Δ

, when the superconducting ground state is evaluated within the weak-coupling BCS theory, and, therefore, are damped. Previously, we have shown that, within the time-dependent Gutzwiller approximation (TDGA), Higgs modes appear inside the gap with a finite binding energy relative to the quasiparticle continuum. Here, we show that the binding energy of the Higgs mode becomes exponentially small in the weak-coupling limit converging to the BCS solution. On the other hand, well-defined undamped amplitude modes exist in strongly coupled superconductors when the interaction energy becomes of the order of the bandwidth. Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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12 pages, 688 KiB

Open AccessArticle

Angularly Selective Enhanced Vortex Screening in Extremely Layered Superconductors with Tilted Columnar Defects

by Gonzalo Rumi, Vincent Mosser, Marcin Konczykowski and Yanina Fasano

Condens. Matter 2024, 9(4), 37; https://doi.org/10.3390/condmat9040037 - 27 Sep 2024

Abstract

We report on two mechanisms of angularly selective enhanced screening in the solid vortex phase of extremely layered superconductors with tilted columnar defects (CDs). We study Bi₂Sr₂CaCu₂O_8+δ samples with different densities of CD tilted 45° [...] Read more.

We report on two mechanisms of angularly selective enhanced screening in the solid vortex phase of extremely layered superconductors with tilted columnar defects (CDs). We study Bi₂Sr₂CaCu₂O_8+δ samples with different densities of CD tilted 45° from the c-axis, and conduct local ac Hall magnetometry measurements, probing the sustainable current of the vortex system. We reveal two types of maxima in sustainable current for particular directions, detected as dips in the magnetic transmittivity of the vortex system. First, for a smaller number of vortices than of defects, an enhancement of screening is detected at an angular location

Θ_{dip}^{1}

∼45° for H applied close to the direction of CD. For a larger number of vortices than of CD,

Θ_{dip}^{1}

decreases towards the

a b

-plane direction upon warming. Second, a pair of additional dips in transmittivity are detected at angles

Θ_{d i p}^{2}

closer to, and quite symmetric with, the

a b

-plane. These two types of angularly selective enhanced screening reveal the effective pinning by tilted CD even for the composite vortex lattices nucleated in tilted fields in Bi₂Sr₂CaCu₂O_8+δ. Full article

(This article belongs to the Section Superconductivity)

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11 pages, 1417 KiB

Open AccessArticle

Collision Dynamics of One-Dimensional Bose–Einstein Condensates

by Aaron Wirthwein, Stephan Haas and Sheng-wey Chiow

Condens. Matter 2024, 9(4), 36; https://doi.org/10.3390/condmat9040036 - 27 Sep 2024

Abstract

We study the collision dynamics of two Bose–Einstein condensates, with their dynamical wave functions modeled by a set of coupled, time-dependent Gross–Pitaevskii equations. In an effective one-dimensional system, we identify regimes characterized by the relationship between inter- and intra-atomic interactions and the initial [...] Read more.

We study the collision dynamics of two Bose–Einstein condensates, with their dynamical wave functions modeled by a set of coupled, time-dependent Gross–Pitaevskii equations. In an effective one-dimensional system, we identify regimes characterized by the relationship between inter- and intra-atomic interactions and the initial configuration of the system, akin to the equilibrium phase diagram of two interacting Bose condensates. We consider a dynamical setup in which two wave packets are initially at rest, with a small separation about the center of an anisotropic harmonic trap. Upon release, we observe a rapid approach to dynamical equilibrium in the limits of very large and very small inter-particle repulsion, characterized by periodic transmission or reflection of the condensates as distinguishable units, whereas the intermediate, critical regime is characterized by extended transient dynamics, density fracturing, and dynamical mixing. Full article

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22 pages, 579 KiB

Open AccessArticle

Towards the Construction of an Analog Solver for the Schrödinger and Ginzburg–Landau Equations Based on a Transmission Line

by Krzysztof Pomorski, Łukasz Pluszyński and Eryk Hałubek

Condens. Matter 2024, 9(4), 35; https://doi.org/10.3390/condmat9040035 - 26 Sep 2024

Abstract

The model presented by Gabriel Kron in 1945 is an example of an analog computer simulating quantum phenomena on a hardware level. It uses passive RLC elements to construct a hardware solver for the problem of quantum particles confined by rectangular or other [...] Read more.

The model presented by Gabriel Kron in 1945 is an example of an analog computer simulating quantum phenomena on a hardware level. It uses passive RLC elements to construct a hardware solver for the problem of quantum particles confined by rectangular or other classes of potential. The analytical and numerical validation of Kron’s second model is conducted for different shapes of particle-confining potentials in the one-dimensional case using an LTspice simulator. Thus, there remains potential for obtaining solutions in two- and three-dimensional cases. Here, a circuit model representing a linearized Ginzburg–Landau equation is given. Kron’s second model is generalized by the introduction of linear and non-linear resistive elements. This transforms the deformed Schrödinger equation into a linear dissipative Schrödinger equation and its non-linear form. The quantum mechanical roton problem is the main result of this work and is formulated by means of classical physical states naturally present in the LC classical circular electrical transmission line. The experimental verification of Kron’s model is confirmed. Full article

(This article belongs to the Special Issue Selected Papers from the International Conference on Quantum Materials and Technologies (ICQMT2024))

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9 pages, 1098 KiB

Open AccessFeature PaperArticle

Room-Temperature Superconductivity in 1D

by Carlo A. Trugenberger

Condens. Matter 2024, 9(3), 34; https://doi.org/10.3390/condmat9030034 - 8 Sep 2024

Abstract

We review the theoretical model underpinning the recently reported room-temperature, ambient-pressure superconductivity along line defects on the surface of highly oriented pyrolytic graphite. The main ingredients for this 1D room-temperature superconductivity are pairing by effective strain gauge fields, the formation of an effective [...] Read more.

We review the theoretical model underpinning the recently reported room-temperature, ambient-pressure superconductivity along line defects on the surface of highly oriented pyrolytic graphite. The main ingredients for this 1D room-temperature superconductivity are pairing by effective strain gauge fields, the formation of an effective Josephson junction array in its Bose metal state on the surface and the suppression of phase slips by dimensional embedding in an extremely well-conducting 3D bulk structure. Full article

(This article belongs to the Special Issue Superstripes Physics, 3rd Edition)

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9 pages, 274 KiB

Open AccessArticle

Remarks on the Quantum Effects of Screw Dislocation Topology and Missing Magnetic Flux

by Knut Bakke

Condens. Matter 2024, 9(3), 33; https://doi.org/10.3390/condmat9030033 - 8 Aug 2024

Abstract

We revisit the interaction between a point charge and an inhomogeneous magnetic field that yields the magnetic quantum dot system. This magnetic field is defined by filling the whole space, except for a region of radius

r_{0}

. Then, we assume that [...] Read more.

We revisit the interaction between a point charge and an inhomogeneous magnetic field that yields the magnetic quantum dot system. This magnetic field is defined by filling the whole space, except for a region of radius

r_{0}

. Then, we assume that there is an impenetrable potential wall located at

r_{0}

and discuss the quantum effects of screw dislocation topology and the missing magnetic flux. We first show that Landau levels can be achieved even though there is the presence of an impenetrable potential wall. We go further by discussing the confinement of a point charge to a cylindrical wire. In both cases, we show Aharonov–Bohm-type effects for bound states can be obtained from the influence of the screw dislocation topology and the missing magnetic flux. Later, we discuss the influence of the screw dislocation topology and the missing magnetic flux on the magnetization and the persistent currents. Full article

(This article belongs to the Section Condensed Matter Theory)

12 pages, 871 KiB

Open AccessArticle

Atomristor Mott Theory of Sn Adatom Adlayer on a Si Surface

by Luis Craco, Edson F. Chagas, Sabrina S. Carara and Byron Freelon

Condens. Matter 2024, 9(3), 32; https://doi.org/10.3390/condmat9030032 - 2 Aug 2024

Abstract

We use a combination of density functional theory (DFT) and dynamical mean field theory (DMFT) to unveil orbital field-induced electronic structure reconstruction of the atomic Sn layer deposited onto a Si(111) surface (Sn/Si(111)−

\sqrt{3} \times \sqrt{3} R 30^{\circ}

), also referred to [...] Read more.

We use a combination of density functional theory (DFT) and dynamical mean field theory (DMFT) to unveil orbital field-induced electronic structure reconstruction of the atomic Sn layer deposited onto a Si(111) surface (Sn/Si(111)−

\sqrt{3} \times \sqrt{3} R 30^{\circ}

), also referred to as

α

-Sn. Our DFT + DMFT results indicate that

α

-Sn is an ideal testing ground to explore electric field-driven orbital selectivity and Mott memory behavior, all arising from the close proximity of

α

-Sn to metal insulator transitions. We discuss the relevance of orbital phase changes for

α

-Sn in the context of the current–voltage (

I - V

) characteristic for future silicon-based metal semiconductor atomristors. Full article

(This article belongs to the Section Condensed Matter Theory)

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13 pages, 5141 KiB

Open AccessArticle

Enhancing the Photoelectrochemical Performance of a Superlattice p–n Heterojunction CuFe₂O₄/ZnFe₂O₄ Electrode for Hydrogen Production

by M. K. Al Turkestani

Condens. Matter 2024, 9(3), 31; https://doi.org/10.3390/condmat9030031 - 26 Jul 2024

Abstract

A p–n heterojunction film consisting of p-type CuFe₂O₄ and n-type ZnFe₂O₄ was fabricated in this study. The n-type ZnFe₂O₄ film was deposited on a stainless steel substrate using the spray pyrolysis method, after which [...] Read more.

A p–n heterojunction film consisting of p-type CuFe₂O₄ and n-type ZnFe₂O₄ was fabricated in this study. The n-type ZnFe₂O₄ film was deposited on a stainless steel substrate using the spray pyrolysis method, after which a top layer of p-type CuFe₂O₄ thin film was deposited and annealed. Characterization techniques, such as X-ray diffraction, scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, and photoluminescence, confirmed the formation of a superlattice p–n heterojunction between CuFe₂O₄ and ZnFe₂O₄. Photoelectrochemical measurements were conducted to investigate the photoelectrochemical properties of the samples, resulting in a photocurrent of 1.2 mA/cm² at 1.5 V (vs. Ag/AgCl) under illumination from a 100-watt LED light source. Utilizing the p–n junction of CuFe₂O₄/ZnFe₂O₄ as a photoanode increased the hydrogen production rate by 30% compared to that of the dark measurement. This enhancement in performance was attributed to the potential barrier at the p–n heterojunction interface, which improved the separation of photoinduced electron–hole pairs and facilitated a more efficient charge transfer. Additionally, coating the stainless steel electrode with this ferrite sample improved both the corrosion resistance and the stability of hydrogen production over extended operation times. Full article

(This article belongs to the Section Physics of Materials)

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11 pages, 3470 KiB

Open AccessArticle

The EuAPS Betatron Radiation Source: Status Update and Photon Science Perspectives

by Federico Galdenzi, Maria Pia Anania, Antonella Balerna, Richard J. Bean, Angelo Biagioni, Claudio Bortolin, Luca Brombal, Francesco Brun, Marcello Coreno, Gemma Costa, Lucio Crincoli, Alessandro Curcio, Martina Del Giorno, Enrico Di Pasquale, Gianluca di Raddo, Valentina Dompè, Sandro Donato, Zeinab Ebrahimpour, Antonio Falone, Andrea Frazzitta, Mario Galletti, Andrea Ghigo, Stefano Lauciani, Andrea Liedl, Valerio Lollo, Augusto Marcelli, Emiliano Principi, Andrea R. Rossi, Federica Stocchi, Fabio Villa, Marco Zottola, Alessandro Cianchi, Francesco Stellato and Massimo Ferrario Show full author list Hide full author list

Condens. Matter 2024, 9(3), 30; https://doi.org/10.3390/condmat9030030 - 22 Jul 2024

Abstract

The EuPRAXIA EU project is at the forefront of advancing particle accelerator research and the development of photon sources through innovative plasma acceleration approaches. Within this framework, the EuAPS project aims to exploit laser wakefield acceleration to build and operate a betatron radiation [...] Read more.

The EuPRAXIA EU project is at the forefront of advancing particle accelerator research and the development of photon sources through innovative plasma acceleration approaches. Within this framework, the EuAPS project aims to exploit laser wakefield acceleration to build and operate a betatron radiation source at the INFN Frascati National Laboratory. The EuAPS source will provide femtosecond X-ray pulses in the spectral region between about 1 and 10 keV, unlocking a realm of experimental ultrafast methodologies encompassing diverse imaging and X-ray spectroscopy techniques. This paper presents a description of the EuAPS betatron source, including simulations of the photon beam parameters, outlines the preliminary design of the dedicated photon beamline, and provides an insightful overview of its photon science applications. Full article

(This article belongs to the Section Spectroscopy and Imaging in Condensed Matter)

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