Physics Open最新文献_第2页

Excellent self-assembly properties of Iron Phthalocyanines on alumina for locally ordered single-atom catalysts 酞菁铁在氧化铝上的自组装性能

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

{"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 理解硅酸钠中复杂阻抗的光谱方法

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

Md Ayub Sheikh , Sudhangshu Chakraborty

{"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 退火对电子用镍掺杂钴纳米铁氧体结构、形貌、光学、磁性和介电性能的影响

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

{"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 杂化钨酸银（Ag2WO4）纳米颗粒改性增强聚乙烯醇/壳聚糖（PVA/Cs）薄膜

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

Aysh Y. Madkhli , Lamiaa G. Alharbe

{"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 亚稳氢原子及其同位素的完整自旋过滤器的研制

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

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

引用次数: 0

Comprehensive first-principle investigation of sodium protactinium oxide (NaPaO3): Unraveling structural, electrical, mechanical, and thermodynamic properties under hydrostatic pressure 综合第一性原理研究氧化镤钠（NaPaO3）：揭示静水压力下的结构、电学、力学和热力学性质

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

{"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 单粒子势对核反应总截面的影响

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

Yan Fan, WenJun Guo, ZiHan Xi

引用次数: 0

Resistive switching mechanisms in BiFeO3 devices with YBCO and Ag as top electrodes 以YBCO和Ag为顶电极的BiFeO3器件的电阻开关机制

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

{"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 γ辐照对PVC/BiVO4/ZnO纳米复合薄膜结构、光学和电子性能的影响

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

{"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

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

{"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