Physics Open最新文献

英文中文

Excellent self-assembly properties of Iron Phthalocyanines on alumina for locally ordered single-atom catalysts

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-22 DOI: 10.1016/j.physo.2025.100259

Fatema Mohamed , Manuel Corva , Erika Tomsič , Zhijing Feng , Tomáš Skála , Giovanni Comelli , Nicola Seriani , Erik Vesselli , Maria Peressi

In a biomimetic approach, metal Phthalocyanines (Pcs) can be considered to efficiently model single atom catalysts (SACs), hosting catalytically active single metal atoms in their macrocyclic cages. An ordered 2D array of SACs can thus be obtained when metal Pcs are assembled in a regular framework. In this work we consider in particular Iron Pcs (FePcs) on an ultra-thin alumina film grown on the Ni₃Al(111) surface. Intrinsic modulations in the potential energy surface related with the oxide film structure drive the self-assembly of FePc molecules into a regular array, with molecular vacancies forming a hexagonal Bravais lattice with the same periodicity of the substrate, i.e. with a lattice parameter of about 4 nm. The symmetry of the supramolecular structure is dictated by the template rather than by the C_4v symmetry of the individual molecules, thus indicating prevalence of molecule-substrate interactions with respect to intermolecular forces. The same hexagonal periodicity extends also to the multilayer, which starts forming already before completion of the first, interfacial monolayer. The latter exhibits a local definite chirality, also propagating to the multilayer in a determined stacking sequence.

{"title":"Excellent self-assembly properties of Iron Phthalocyanines on alumina for locally ordered single-atom catalysts","authors":"Fatema Mohamed , Manuel Corva , Erika Tomsič , Zhijing Feng , Tomáš Skála , Giovanni Comelli , Nicola Seriani , Erik Vesselli , Maria Peressi","doi":"10.1016/j.physo.2025.100259","DOIUrl":"10.1016/j.physo.2025.100259","url":null,"abstract":"<div><div>In a biomimetic approach, metal Phthalocyanines (Pcs) can be considered to efficiently model single atom catalysts (SACs), hosting catalytically active single metal atoms in their macrocyclic cages. An ordered 2D array of SACs can thus be obtained when metal Pcs are assembled in a regular framework. In this work we consider in particular Iron Pcs (FePcs) on an ultra-thin alumina film grown on the Ni<sub>3</sub>Al(111) surface. Intrinsic modulations in the potential energy surface related with the oxide film structure drive the self-assembly of FePc molecules into a regular array, with molecular vacancies forming a hexagonal Bravais lattice with the same periodicity of the substrate, i.e. with a lattice parameter of about 4 nm. The symmetry of the supramolecular structure is dictated by the template rather than by the C<sub>4v</sub> symmetry of the individual molecules, thus indicating prevalence of molecule-substrate interactions with respect to intermolecular forces. The same hexagonal periodicity extends also to the multilayer, which starts forming already before completion of the first, interfacial monolayer. The latter exhibits a local definite chirality, also propagating to the multilayer in a determined stacking sequence.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100259"},"PeriodicalIF":0.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spectroscopic approach to understanding complex impedance in sodium silicate

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-13 DOI: 10.1016/j.physo.2025.100255

Md Ayub Sheikh , Sudhangshu Chakraborty

This study investigates the complex impedance spectroscopy (CIS) of sodium silicate (Na₂SiO₃) across various frequencies and temperatures to examine the influence of grain and grain boundary polarization on its electrical properties. The findings reveal a non-Debye relaxation behavior, deviating from ideal relaxation models typically observed in such materials. Both dielectric relaxation and dispersion effects contribute to the polaron-controlled hopping mechanism evident in the CIS data.The Nyquist plot exhibits a single semicircular arc, indicating that grain boundary polarization is the dominant factor affecting the impedance of sodium silicate. Additionally, the study explores the correlated barrier-hopping model, providing insights into AC conductivity behavior across different frequency ranges. This comprehensive analysis enhances the understanding of sodium silicate's electrical properties, which is crucial for potential applications in materials science, particularly in contexts where polarization effects and conductivity mechanisms play a key role. Beyond fundamental insights, the research offers practical implications for optimizing material performance in related fields.

{"title":"Spectroscopic approach to understanding complex impedance in sodium silicate","authors":"Md Ayub Sheikh , Sudhangshu Chakraborty","doi":"10.1016/j.physo.2025.100255","DOIUrl":"10.1016/j.physo.2025.100255","url":null,"abstract":"<div><div>This study investigates the complex impedance spectroscopy (CIS) of sodium silicate (Na₂SiO₃) across various frequencies and temperatures to examine the influence of grain and grain boundary polarization on its electrical properties. The findings reveal a non-Debye relaxation behavior, deviating from ideal relaxation models typically observed in such materials. Both dielectric relaxation and dispersion effects contribute to the polaron-controlled hopping mechanism evident in the CIS data.The Nyquist plot exhibits a single semicircular arc, indicating that grain boundary polarization is the dominant factor affecting the impedance of sodium silicate. Additionally, the study explores the correlated barrier-hopping model, providing insights into AC conductivity behavior across different frequency ranges. This comprehensive analysis enhances the understanding of sodium silicate's electrical properties, which is crucial for potential applications in materials science, particularly in contexts where polarization effects and conductivity mechanisms play a key role. Beyond fundamental insights, the research offers practical implications for optimizing material performance in related fields.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100255"},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of annealing on the structural, morphological, optical, magnetic, and dielectric properties of nickel-doped cobalt nanoferrites for electronic applications

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2024.100250

Md Shihabun Sakib , Md Naimur Rahman , Md Alamgir Hossain , Md Rashedur Rahman

Nanocrystalline powders of nickel-substituted cobalt ferrite were synthesized using the chemical co-precipitation method with ammonia solution as the precipitating agent, maintaining a nickel-to-iron mole ratio of 1:3. The effects of annealing at 600 °C, 650 °C, 700 °C, and 750 °C on the structural, morphological, optical, magnetic, and dielectric properties of the samples were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), a UV–vis–NIR spectrophotometer (UV), a vibrating sample magnetometer (VSM), and an impedance analyzer. X-ray diffraction analysis confirmed the f.c.c spinel structure with an Fd3m symmetric space group, and crystallite sizes increased from 15.96 to 19.11 nm with higher annealing temperatures. SEM revealed nanoparticle sizes of 362.14–444.88 nm, each comprising 22–23 crystals. UV spectroscopy indicated semiconductor behavior with band gaps ranging from 1.86 to 2.15 eV. Dielectric constant and losses decreased with higher annealing temperature and frequency. Annealing affected interionic bond lengths, distances, and angles, resulting in an increase in coercivity from 77.15 to 117.70 Oe, while saturation magnetization decreased from 9.15 to 5.32 emu/g, indicating the soft magnetic properties of CNSF nanoparticles. The Curie temperature dropped from 551.29 °C to 379.55 °C as temperature increased. The experimental results align with reported values, showing that higher annealing temperatures provide optimal structural, morphological, and magnetic properties, while lower temperatures favor optical and dielectric properties in CNSF nanoparticles.

{"title":"Effect of annealing on the structural, morphological, optical, magnetic, and dielectric properties of nickel-doped cobalt nanoferrites for electronic applications","authors":"Md Shihabun Sakib , Md Naimur Rahman , Md Alamgir Hossain , Md Rashedur Rahman","doi":"10.1016/j.physo.2024.100250","DOIUrl":"10.1016/j.physo.2024.100250","url":null,"abstract":"<div><div>Nanocrystalline powders of nickel-substituted cobalt ferrite were synthesized using the chemical co-precipitation method with ammonia solution as the precipitating agent, maintaining a nickel-to-iron mole ratio of 1:3. The effects of annealing at 600 °C, 650 °C, 700 °C, and 750 °C on the structural, morphological, optical, magnetic, and dielectric properties of the samples were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), a UV–vis–NIR spectrophotometer (UV), a vibrating sample magnetometer (VSM), and an impedance analyzer. X-ray diffraction analysis confirmed the f.c.c spinel structure with an Fd<em>3</em>m symmetric space group, and crystallite sizes increased from 15.96 to 19.11 nm with higher annealing temperatures. SEM revealed nanoparticle sizes of 362.14–444.88 nm, each comprising 22–23 crystals. UV spectroscopy indicated semiconductor behavior with band gaps ranging from 1.86 to 2.15 eV. Dielectric constant and losses decreased with higher annealing temperature and frequency. Annealing affected interionic bond lengths, distances, and angles, resulting in an increase in coercivity from 77.15 to 117.70 Oe, while saturation magnetization decreased from 9.15 to 5.32 emu/g, indicating the soft magnetic properties of CNSF nanoparticles. The Curie temperature dropped from 551.29 °C to 379.55 °C as temperature increased. The experimental results align with reported values, showing that higher annealing temperatures provide optimal structural, morphological, and magnetic properties, while lower temperatures favor optical and dielectric properties in CNSF nanoparticles.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"22 ","pages":"Article 100250"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modified and enhancement polyvinyl alcohol/chitosan (PVA/Cs) films incorporated by hybrid silver tungstate (Ag2WO4) nanoparticles

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2024.100247

Aysh Y. Madkhli , Lamiaa G. Alharbe

This study aims to synthesize silver tungstate (Ag₂WO₄) nanoparticles and incorporate them into a polyvinyl alcohol/chitosan (PVA/Cs) blend using a casting technique. X-ray diffraction (XRD) analysis confirms the presence of peaks corresponding to silver and tungsten, indicating the presence of these elements in the analyzed samples and providing conclusive evidence of their existence. The XRD profiles also revealed characteristic peaks corresponding to the monoclinic unit cell of PVA and an allomorphic transition within the chitosan structure. After adding Ag₂WO₄ nanoparticles, XRD analysis exhibited peaks for silver and tungsten with a crystallite size of 42.2 ± 3 nm. The UV–visible measurements indicate that incorporating Ag₂WO₄ causes a decrease in band gap energy values from 4.71 to 2.38 eV and from 5.8 to 3.73 eV for the direct allowed and direct forbidden transitions, respectively. Furthermore, the optical constants, including the extinction coefficient (k), real (

ε^{'}

), and imaginary (

ε^{″}

) parts, as well as the optical dielectric conductivity, were thoroughly discussed. Photoluminescence (PL) analysis revealed the emergence of a broad band centered at 434 nm with increasing Ag₂WO₄ concentration, indicating changes in the emission properties of the nanocomposites. The dielectric properties and the electrical modulus (Mʹ) values increased at higher frequencies, indicating charge carrier transfer through short-range mobility. The imaginary part (Mʹʹ) exhibited a peak attributed to dipolar polarization at the interfaces between grains, which experienced a frequency shift towards higher values. This shift indicates alterations in the distribution of Ag₂WO₄ within the PVA/Cs blend. These nanocomposites show potential in energy storage devices.

{"title":"Modified and enhancement polyvinyl alcohol/chitosan (PVA/Cs) films incorporated by hybrid silver tungstate (Ag2WO4) nanoparticles","authors":"Aysh Y. Madkhli , Lamiaa G. Alharbe","doi":"10.1016/j.physo.2024.100247","DOIUrl":"10.1016/j.physo.2024.100247","url":null,"abstract":"<div><div>This study aims to synthesize silver tungstate (Ag<sub>2</sub>WO<sub>4</sub>) nanoparticles and incorporate them into a polyvinyl alcohol/chitosan (PVA/Cs) blend using a casting technique. X-ray diffraction (XRD) analysis confirms the presence of peaks corresponding to silver and tungsten, indicating the presence of these elements in the analyzed samples and providing conclusive evidence of their existence. The XRD profiles also revealed characteristic peaks corresponding to the monoclinic unit cell of PVA and an allomorphic transition within the chitosan structure. After adding Ag<sub>2</sub>WO<sub>4</sub> nanoparticles, XRD analysis exhibited peaks for silver and tungsten with a crystallite size of 42.2 ± 3 nm. The UV–visible measurements indicate that incorporating Ag<sub>2</sub>WO<sub>4</sub> causes a decrease in band gap energy values from 4.71 to 2.38 eV and from 5.8 to 3.73 eV for the direct allowed and direct forbidden transitions, respectively. Furthermore, the optical constants, including the extinction coefficient (k), real (<span><math><mrow><msup><mi>ε</mi><mo>′</mo></msup></mrow></math></span>), and imaginary (<span><math><mrow><msup><mi>ε</mi><mo>″</mo></msup></mrow></math></span>) parts, as well as the optical dielectric conductivity, were thoroughly discussed. Photoluminescence (PL) analysis revealed the emergence of a broad band centered at 434 nm with increasing Ag<sub>2</sub>WO<sub>4</sub> concentration, indicating changes in the emission properties of the nanocomposites. The dielectric properties and the electrical modulus (Mʹ) values increased at higher frequencies, indicating charge carrier transfer through short-range mobility. The imaginary part (Mʹʹ) exhibited a peak attributed to dipolar polarization at the interfaces between grains, which experienced a frequency shift towards higher values. This shift indicates alterations in the distribution of Ag<sub>2</sub>WO<sub>4</sub> within the PVA/Cs blend. These nanocomposites show potential in energy storage devices.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"22 ","pages":"Article 100247"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a complete spin filter for metastable hydrogen atoms and its isotopes

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2024.100248

N. Faatz , R. Engels , C. Kannis , B. Breitkreutz , H. Soltner

Since the early days of quantum mechanics, hydrogen, as the simplest of all atoms, has been studied or used to investigate new physics. In the past this knowledge has been applied to develop a polarimeter where the initial nuclear polarization of a proton beam could be determined. The key component of this Lamb-shift polarimeter is the so called spin filter, which is able to separate one of four metastable hydrogen hyperfine states by quenching the remaining three hyperfine states to the ground state. Unfortunately, the conventional spin filter is only able to filter two out of the four hyperfine states individually. Therefore, this work provides the necessary theory as well as experimental conditions to build a new generation of spin filter which permits the separation and transmission of any metastable hydrogen hyperfine state as well as for its isotopes in a corresponding beam. This knowledge is applicable for other experiments in different fields of research, e.g. the bound beta decay, axion research or parity violation experiments.

引用次数: 0

Comprehensive first-principle investigation of sodium protactinium oxide (NaPaO3): Unraveling structural, electrical, mechanical, and thermodynamic properties under hydrostatic pressure

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2025.100254

Md Kaab Bin Hossen, Istiak Ahmed Ovi, Md Anas Bin Hossen, Md Adil Hossain

Perovskite materials have gained substantial attention in materials science and engineering for their numerous applications. For potential solar material & optoelectronic application it was analyzed in this study using the density functional theory (DFT). Specifically, the structural along with the electrical, thermodynamic, optical, and mechanical properties of NaPaO₃ were investigated under different hydrostatic pressures, ranging from 0 to 60 GPa. The pressure-induced effects were characterized by a reduction in interatomic distance, resulting in a significant decrease in the lattice constant and unit cell volume of the perovskite structure. Utilizing the generalized gradient approximation (GGA), the study delved into the equilibrium structural properties, elastic characteristics, energy band structure, and density of states of NaPaO₃. The compound shows mechanical stability in all structural configurations when pressure is applied up to 60 GPa. The compound exhibits a transition from ductile to brittle behavior, with the B/G ratio rising from 2.188 at 0 GPa to 10.422 at 60 GPa, indicating increased stiffness and reduced deformability under pressure. The band structure, initially found at 3.208 eV under normal pressure, approaches the Fermi level with increasing pressure, indicating its potential in semiconductor applications. Detailed analyses of band structures, and partial & total density of states (PDOS and TDOS) reveal the electronic behaviors of the compound. NaPaO₃ exhibited remarkable mechanical and optoelectronic attributes under hydrostatic pressure, making it a strong candidate for applications in photovoltaics and solar panel technologies.

{"title":"Comprehensive first-principle investigation of sodium protactinium oxide (NaPaO3): Unraveling structural, electrical, mechanical, and thermodynamic properties under hydrostatic pressure","authors":"Md Kaab Bin Hossen, Istiak Ahmed Ovi, Md Anas Bin Hossen, Md Adil Hossain","doi":"10.1016/j.physo.2025.100254","DOIUrl":"10.1016/j.physo.2025.100254","url":null,"abstract":"<div><div>Perovskite materials have gained substantial attention in materials science and engineering for their numerous applications. For potential solar material & optoelectronic application it was analyzed in this study using the density functional theory (DFT). Specifically, the structural along with the electrical, thermodynamic, optical, and mechanical properties of NaPaO<sub>3</sub> were investigated under different hydrostatic pressures, ranging from 0 to 60 GPa. The pressure-induced effects were characterized by a reduction in interatomic distance, resulting in a significant decrease in the lattice constant and unit cell volume of the perovskite structure. Utilizing the generalized gradient approximation (GGA), the study delved into the equilibrium structural properties, elastic characteristics, energy band structure, and density of states of NaPaO<sub>3</sub>. The compound shows mechanical stability in all structural configurations when pressure is applied up to 60 GPa. The compound exhibits a transition from ductile to brittle behavior, with the B/G ratio rising from 2.188 at 0 GPa to 10.422 at 60 GPa, indicating increased stiffness and reduced deformability under pressure. The band structure, initially found at 3.208 eV under normal pressure, approaches the Fermi level with increasing pressure, indicating its potential in semiconductor applications. Detailed analyses of band structures, and partial & total density of states (PDOS and TDOS) reveal the electronic behaviors of the compound. NaPaO<sub>3</sub> exhibited remarkable mechanical and optoelectronic attributes under hydrostatic pressure, making it a strong candidate for applications in photovoltaics and solar panel technologies.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"22 ","pages":"Article 100254"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of single particle potential on total cross section of nuclear reaction

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2025.100251

Yan Fan, WenJun Guo, ZiHan Xi

In nuclear physics,the calculation of reaction cross-sections is an essential method for studying nuclear structure.By investigating the reaction cross-sections of different elements colliding with ¹²C and analyzing the data, insights into nuclear structure and the nature of interactions between particles can be gained.This study employs the Isospin Quantum Molecular Dynamics model (IQMD) to examine reaction cross-sections of collisions between various nuclei and ¹²C at specific energies.The calculated results show excellent agreement with experimental data. Using this method, reaction cross-sections for proton-proton,proton-neutron,and neutron-neutron interactions are computed. Subsequently,the same approach is applied to calculate the total cross-section of nuclear reactions between carbon isotopes. The research indicates that the magnitude of the total cross-section is influenced by the isospin effects of particles and is also correlated with the number of free neutrons and protons produced in the reaction.

引用次数: 0

Resistive switching mechanisms in BiFeO3 devices with YBCO and Ag as top electrodes

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-02-01 DOI: 10.1016/j.physo.2024.100249

Santiago Ceballos Medina , Lorena Marín Mercado , Alexander Cardona-Rodríguez , Mario Fernando Quiñonez Penagos , César Magén , Luis Alfredo Rodríguez , Juan Gabriel Ramírez

The resistive switching (RS) effect in ferroelectric oxides continues to attract significant attention due to its potential applications in nonvolatile memory and neuromorphic computing devices. In this study, we investigate the RS properties of BiFeO₃/YBa₂Cu₃O_7−d (BFO/YBCO) bilayers grown on LSAT substrates, comparing two different top-electrode materials: YBCO and Ag. The devices were fabricated using reactive sputtering at high oxygen pressure, and their RS mechanisms were investigated via current-voltage (I-V) measurements. We find all devices exhibit unipolar behavior, with symmetric RS behavior observed in devices with YBCO top electrodes and asymmetric RS in those with Ag top electrodes. Devices with YBCO top electrodes display ohmic conduction, whereas Ag top electrode devices exhibit a combination of Schottky, Poole-Frenkel emission, and spaced charge limited conduction mechanisms. Resistance versus time measurements were performed over 30 cycles with 20 different writing voltages to evaluate the ratio between the low resistance state (LRS) and high resistance state (HRS). Ag top electrodes devices consistently exhibited higher resistance ratios ‒approximately three times larger‒ compared to YBCO devices. Furthermore, better temporal stability of HRS and LRS was observed in devices with Ag top electrodes, attributed to the differences in the Fermi energy levels between YBCO, Ag and BFO. The superior performance of Ag top electrode devices, including their higher storage density and low operation parameters (0.25 V and 5 nA), highlights their potential for energy-efficient applications in future oxide-based memory and neuromorphic devices.

{"title":"Resistive switching mechanisms in BiFeO3 devices with YBCO and Ag as top electrodes","authors":"Santiago Ceballos Medina , Lorena Marín Mercado , Alexander Cardona-Rodríguez , Mario Fernando Quiñonez Penagos , César Magén , Luis Alfredo Rodríguez , Juan Gabriel Ramírez","doi":"10.1016/j.physo.2024.100249","DOIUrl":"10.1016/j.physo.2024.100249","url":null,"abstract":"<div><div>The resistive switching (RS) effect in ferroelectric oxides continues to attract significant attention due to its potential applications in nonvolatile memory and neuromorphic computing devices. In this study, we investigate the RS properties of BiFeO<sub>3</sub>/YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−d</sub> (BFO/YBCO) bilayers grown on LSAT substrates, comparing two different top-electrode materials: YBCO and Ag. The devices were fabricated using reactive sputtering at high oxygen pressure, and their RS mechanisms were investigated via current-voltage (I-V) measurements. We find all devices exhibit unipolar behavior, with symmetric RS behavior observed in devices with YBCO top electrodes and asymmetric RS in those with Ag top electrodes. Devices with YBCO top electrodes display ohmic conduction, whereas Ag top electrode devices exhibit a combination of Schottky, Poole-Frenkel emission, and spaced charge limited conduction mechanisms. Resistance versus time measurements were performed over 30 cycles with 20 different writing voltages to evaluate the ratio between the low resistance state (LRS) and high resistance state (HRS). Ag top electrodes devices consistently exhibited higher resistance ratios ‒approximately three times larger‒ compared to YBCO devices. Furthermore, better temporal stability of HRS and LRS was observed in devices with Ag top electrodes, attributed to the differences in the Fermi energy levels between YBCO, Ag and BFO. The superior performance of Ag top electrode devices, including their higher storage density and low operation parameters (0.25 V and 5 nA), highlights their potential for energy-efficient applications in future oxide-based memory and neuromorphic devices.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"22 ","pages":"Article 100249"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of gamma irradiation on the structural, optical, and electronic properties of PVC/BiVO4/ZnO nanocomposite films

Q2 Physics and Astronomy

Physics Open

Pub Date : 2025-01-31 DOI: 10.1016/j.physo.2025.100252

Badriah Alshahrani , Soad Saad Fares , Rania Saleh Alqurashi , Montasir Salman , Ahmad Hassan Korna

This study investigates the impact of gamma irradiation on the structural, optical, and electronic properties of PVC/BiVO₄/ZnO nanocomposite films. Gamma irradiation induced significant modifications, including a decrease in BiVO₄ crystallinity, a redshift in the optical bandgap, and a decrease in photoluminescence intensity. These changes suggest alterations in the electronic structure and charge carrier dynamics within the nanocomposite. While gamma irradiation led to a decrease in crystallinity, the observed bandgap reduction could potentially be exploited to enhance photocatalytic activity by allowing the absorption of a wider range of visible light. Further research is warranted to optimize irradiation conditions and investigate the photocatalytic performance of the irradiated films. These findings provide valuable insights into the potential of gamma irradiation as a tool for tailoring the properties of PVC/BiVO₄/ZnO nanocomposites for various applications, including photocatalysis, sensors, and optoelectronic devices.

{"title":"Effect of gamma irradiation on the structural, optical, and electronic properties of PVC/BiVO4/ZnO nanocomposite films","authors":"Badriah Alshahrani , Soad Saad Fares , Rania Saleh Alqurashi , Montasir Salman , Ahmad Hassan Korna","doi":"10.1016/j.physo.2025.100252","DOIUrl":"10.1016/j.physo.2025.100252","url":null,"abstract":"<div><div>This study investigates the impact of gamma irradiation on the structural, optical, and electronic properties of PVC/BiVO<sub>4</sub>/ZnO nanocomposite films. Gamma irradiation induced significant modifications, including a decrease in BiVO<sub>4</sub> crystallinity, a redshift in the optical bandgap, and a decrease in photoluminescence intensity. These changes suggest alterations in the electronic structure and charge carrier dynamics within the nanocomposite. While gamma irradiation led to a decrease in crystallinity, the observed bandgap reduction could potentially be exploited to enhance photocatalytic activity by allowing the absorption of a wider range of visible light. Further research is warranted to optimize irradiation conditions and investigate the photocatalytic performance of the irradiated films. These findings provide valuable insights into the potential of gamma irradiation as a tool for tailoring the properties of PVC/BiVO<sub>4</sub>/ZnO nanocomposites for various applications, including photocatalysis, sensors, and optoelectronic devices.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100252"},"PeriodicalIF":0.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analytical treatment of the Yukawa screened Coulomb interaction in a plane-wave basis 汤川屏蔽库仑相互作用平面波基的解析处理

Q2 Physics and Astronomy

Physics Open

Pub Date : 2024-11-26 DOI: 10.1016/j.physo.2024.100243

Priyanka Aggarwal , Ram Kuntal Hazra , Bharti Kapil , Shivalika Sharma , Igor Di Marco

The calculation of the many-electron (screened) Coulomb and exchange integrals is a very common task to perform in modern electronic structure theory. While an analytical treatment of the complete integrals is too complicated to be attempted directly, essential insight can be gained by focusing on the most significant contributions, as determined by a physical criterion. The monopole term of the screened Coulomb interaction is particularly important, since it defines the Hubbard interaction

U

among a set of localized electrons, which is an essential parameter for effective models of strongly correlated systems. Here, we derive an analytical solution for the matrix elements of the screened Coulomb interaction on a plane-wave basis, which is routinely used in the most common methods for electronic structure calculations. Screening is treated using a Yukawa potential, which is suitable to describe the valence electrons in the Fermi level region. For the solution of the integrals, the plane waves and the Yukawa potential are first expanded in Bessel functions of first and second kind. Then, by means of the lower and upper incomplete gamma functions, we are able to obtain closed-form integrals of a series that remains convergent for realistic parameters. Our exact solution for the radial integrals of the monopole term can find usage in plane-wave codes for electronic structure calculations, both as an output tool as well as within the computational cycle, as e.g., for many-body extensions of density-functional theory. Considering the importance of Bessel functions in solid state physics and electronic structure theory, it is also easy to foresee that our solution to the various integrals across this work may become useful to several other problems in the field.

在现代电子结构理论中，多电子（屏蔽）库仑积分和交换积分的计算是一项非常常见的任务。虽然对完整积分的解析处理过于复杂，无法直接尝试，但通过关注由物理标准确定的最重要的贡献，可以获得基本的见解。筛选库仑相互作用的单极项特别重要，因为它定义了一组局域电子之间的Hubbard相互作用U，这是强相关系统有效模型的重要参数。在这里，我们推导了屏蔽库仑相互作用在平面波基础上的矩阵元素的解析解，这通常用于最常见的电子结构计算方法。使用汤川势进行筛选，汤川势适用于描述费米能级区域的价电子。对于积分的解，首先将平面波和汤川势展开为第一类和第二类贝塞尔函数。然后，利用上下不完全函数，我们能够得到对实际参数保持收敛的级数的闭型积分。我们对单极项径向积分的精确解可以在电子结构计算的平面波代码中找到用途，既可以作为输出工具，也可以在计算周期内使用，例如密度泛函理论的多体扩展。考虑到贝塞尔函数在固态物理和电子结构理论中的重要性，也很容易预见，我们对这项工作中各种积分的解决方案可能对该领域的其他几个问题有用。

{"title":"Analytical treatment of the Yukawa screened Coulomb interaction in a plane-wave basis","authors":"Priyanka Aggarwal , Ram Kuntal Hazra , Bharti Kapil , Shivalika Sharma , Igor Di Marco","doi":"10.1016/j.physo.2024.100243","DOIUrl":"10.1016/j.physo.2024.100243","url":null,"abstract":"<div><div>The calculation of the many-electron (screened) Coulomb and exchange integrals is a very common task to perform in modern electronic structure theory. While an analytical treatment of the complete integrals is too complicated to be attempted directly, essential insight can be gained by focusing on the most significant contributions, as determined by a physical criterion. The monopole term of the screened Coulomb interaction is particularly important, since it defines the Hubbard interaction <span><math><mi>U</mi></math></span> among a set of localized electrons, which is an essential parameter for effective models of strongly correlated systems. Here, we derive an analytical solution for the matrix elements of the screened Coulomb interaction on a plane-wave basis, which is routinely used in the most common methods for electronic structure calculations. Screening is treated using a Yukawa potential, which is suitable to describe the valence electrons in the Fermi level region. For the solution of the integrals, the plane waves and the Yukawa potential are first expanded in Bessel functions of first and second kind. Then, by means of the lower and upper incomplete gamma functions, we are able to obtain closed-form integrals of a series that remains convergent for realistic parameters. Our exact solution for the radial integrals of the monopole term can find usage in plane-wave codes for electronic structure calculations, both as an output tool as well as within the computational cycle, as e.g., for many-body extensions of density-functional theory. Considering the importance of Bessel functions in solid state physics and electronic structure theory, it is also easy to foresee that our solution to the various integrals across this work may become useful to several other problems in the field.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"22 ","pages":"Article 100243"},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

下一页尾页

类型

全部化学•材料生命科学医学物理工程技术环境•农林材料科学地球科学法学管理学化学环境科学与生态学计算机科学教育学经济学农林科学人文科学生物学数学物理与天体物理心理学综合性期刊其他工业工程理学历史学农学文学信息工程

数据库

全部 ACS Publications Elsevier ieeexplore Springer The Royal Society of Chemistry Wiley

期刊

Physics Open

全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.

﹀