Physics Open最新文献

{"title":"Anisotropic and tunable properties of hydrogen/halogen-terminated germanene nanoribbons for advanced optoelectronics","authors":"K. Gherbi ,&nbsp;M.T. Kadri ,&nbsp;H. Belkhir ,&nbsp;K. Zanat","doi":"10.1016/j.physo.2025.100280","DOIUrl":"10.1016/j.physo.2025.100280","url":null,"abstract":"<div><div>This study explores the structural, electronic, and optical characteristics of X-terminated germanene nanoribbons (GeNRs) featuring armchair (7-AGeNR) and zigzag (5-ZGeNR) arrangements through first-principles calculations. The findings illustrate how halogen edge functionalization (H, F, Cl, Br, I) significantly modifies the geometric, electronic, and optical traits of GeNRs. Specifically, the Ge-Ge bond length (2.44 Å) and the buckling height (0.69 Å) of the 7-AGeNRs are affected by the size of the X-terminated atoms, with larger halogens leading to increased bond lengths and changes in electronic properties. The analysis of the electronic band structure indicates that halogen passivation introduces a bandgap in the nanoribbons, with 7-AGeNRs-F displaying the largest bandgap of 0.60 eV, as opposed to 0.37 eV for 7-AGeNRs-I. We provide new insights into the tunable anisotropy of the dielectric constant and distinct optical transitions induced by halogen edge functionalization. The optical properties exhibit notable anisotropy, with 7-AGeNR-H showing a dielectric constant of <span><math><mrow><msubsup><mi>ε</mi><mn>1</mn><mrow><mi>x</mi><mi>x</mi></mrow></msubsup><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow><mo>=</mo><mn>12.984</mn></mrow></math></span> and <span><math><mrow><msubsup><mi>ε</mi><mn>1</mn><mrow><mi>y</mi><mi>y</mi></mrow></msubsup><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow><mo>=</mo><mn>4.127</mn></mrow></math></span>, while I-termination leads to reduced values of 7.762 and 5.031, respectively. Furthermore, a redshift in absorption is observed for 7-AGeNRs with heavier halogens, while 5-ZGeNRs demonstrate a blueshift. Reflectivity and plasma frequency analyses point to an optical anisotropy, where H-terminated 7-AGeNR shows a high reflectivity of <span><math><mrow><msup><mi>R</mi><mrow><mi>x</mi><mi>x</mi></mrow></msup><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow><mo>=</mo><mn>0.320</mn></mrow></math></span>, which diminishes with heavier halogens. These adjustable properties indicate the potential application of GeNRs in optoelectronic devices, including infrared (IR) detectors, ultraviolet (UV) sensors, and photovoltaic systems.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100280"},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensing response of aluminum-side-polished fiber-based surface plasmon resonance sensors to surface roughness","authors":"Yuqi Han ,&nbsp;Jieyuan Tang ,&nbsp;Jianshang Liao ,&nbsp;Li Tan","doi":"10.1016/j.physo.2025.100281","DOIUrl":"10.1016/j.physo.2025.100281","url":null,"abstract":"<div><div>Aluminum is a widely used and cost-effective material for marine equipment because of its strong adhesion and simple coating processes. This study utilizes finite element numerical analysis to examine the sensing characteristics and sensitivity of aluminum-side-polished fiber (SPF) surface plasmon resonance (SPR) sensors with varying aluminum film thicknesses. Additionally, it investigates the response characteristics of these sensors to different surface roughness morphologies. The simulation results reveal that for SPF-based SPR sensors with a remaining thickness of 1 μm under a wavelength of 1550 nm, the coupling depth of the SPR resonance peak initially deepens and then shallow increases as the aluminum film thickness increases from 20 nm to 50 nm, achieving maximum coupling depth and sensitivity of 857 nm/RIU at 30 nm thickness. Models of aluminum-SPF-based SPR sensors were developed for ideally smooth, periodically rough, and randomly rough surface morphologies. The simulations reveal that as the surface morphology of the fiber transitions from smooth to periodically rough to randomly rough, the SPR resonance peak shifts from 961 nm to 954 nm and then to 885 nm, with the blue shift range increasing as the random roughness of the fiber surface intensifies. These simulations confirm the efficacy of aluminum-SPF-based SPR sensors in detecting variations in surface roughness morphology, establishing a theoretical foundation for the further application of these sensors in developing new sensing platforms for detecting corrosion in marine equipment materials in marine environments.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100281"},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First-principles investigation of NaGeX3 (X = Cl, Br, I) perovskites for eco-friendly photovoltaic and optoelectronic applications","authors":"Mohammad Nazmul Hasan ,&nbsp;Md N.J. Rifat ,&nbsp;Jahid Kabir Rony ,&nbsp;Md Saiduzzaman ,&nbsp;Minhajul Islam","doi":"10.1016/j.physo.2025.100278","DOIUrl":"10.1016/j.physo.2025.100278","url":null,"abstract":"<div><div>Cubic-structured perovskite compounds used in solar cells, made without lead (Pb) or other harmful materials, are becoming increasingly important as photovoltaic systems gain commercial viability. This investigation models the structural, mechanical, electronic, bonding, and optical behavior of Pb-free inorganic metal-halide cubic perovskite compounds NaGeX₃ (X = Cl, Br, I) for advanced microelectronics using first-principles density functional theory calculations. The lattice constants for NaGeCl₃ (5.226 Å), NaGeBr₃ (5.498 Å), and NaGeI₃ (5.893 Å) show excellent agreement with previously published data. The studied compounds are semiconductors with optimized band gaps and are found to be structurally, thermodynamically, mechanically, and vibrationally stable. The sX functional was utilized to enhance the accuracy of the energy band gap calculations, resulting in significantly improved band gap values for NaGeCl₃ (1.76 eV), NaGeBr₃ (1.65 eV), and NaGeI₃ (1.22 eV). The calculated ductility, Vickers hardness, and machinability index values exhibit the following trend: NaGeCl₃ &gt; NaGeBr₃ &gt; NaGeI₃. The compounds are suited for use in photovoltaic devices such as solar cells and other optoelectronic sensor systems because they have excellent optical conductivity, a high absorption coefficient, and low reflectance. It can be considered whether germanium (Ge) could serve as a suitable substitute for Pb, given its optical properties, as Ge-containing compounds demonstrate enhanced optical absorption and optical conductivity. In accordance with a comparative assessment of the compounds' electronic, optical, and mechanical behavior, NaGeI₃-based perovskite is the optimal comparative to Pb-free inorganic metal-halide perovskite semiconductor for the usage of solar cells. This investigation offers valuable insights for developing lead-free inorganic perovskites suitable for optoelectronic applications and serves as a theoretical foundation to support future experimental validation of the selected compounds for practical use.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100278"},"PeriodicalIF":0.0,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mean first passage time as a natural diffusion distance","authors":"Maxim J. Goldberg ,&nbsp;Seonja Kim","doi":"10.1016/j.physo.2025.100271","DOIUrl":"10.1016/j.physo.2025.100271","url":null,"abstract":"<div><div>Given an irreducible finite Markov chain, we propose the mean first passage time (MFPT) as a diffusion distance. We motivate this definition by considering a compact Riemannian manifold, and the submanifold resulting from removing the closure of a small ball. The steady-state solution to an associated inhomogeneous heat flow problem on the submanifold is non-negative and can be viewed as having large values at locations which are “far” away from the removed ball. The same function is also shown, at any point, to “count”, via probability, the paths starting at that point which miss the ball. As a third viewpoint, the same function gives the expected value of the first hitting time of the removed ball. The latter interpretation leads to our proposing the MFPT as a diffusion distance for a given finite set of states (samples) and an associated transition matrix. Even if the transition matrix does not arise from heat flow, and may in fact be non-symmetric and non-bistochastic, we note that the MFPT satisfies the triangle inequality. Moreover, various efficient ways to compute the MFPT, and approximations to the MFPT, have been proposed in the literature.</div><div>Additionally, we establish a novel connection between certain mean first passage times and the sum of squares of Coifman-Lafon diffusion distances across all scales.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100271"},"PeriodicalIF":0.0,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"\"Effect of Cd2+ substitution on the structural, magnetic, and dielectric properties of Li-Ni spinel ferrite nanoparticles synthesized via sol-gel method.\"","authors":"Dhanraj N. Aepurwar ,&nbsp;V.J.S.N. Prasad ,&nbsp;B.H. Devmunde","doi":"10.1016/j.physo.2025.100273","DOIUrl":"10.1016/j.physo.2025.100273","url":null,"abstract":"<div><div>Cadmium-doped lithium-nickel ferrite (Cd_<em>x</em>Li_{0.4-<em>x</em>/2}Ni_0.2Fe_{2.4-<em>x</em>/2}O₄) nanoparticles with doping content (<em>x</em> = 0.0 to 0.3) were synthesized via sol-gel auto combustion technique. The X-ray diffraction (XRD) studies have confirmed the cubic spinel structure. The crystallite size was calculated using Scherrer's formula, determined in the range of 37–29 nm. Field emission transmission electron microscopy (FETEM) further estimates particle size at ∼100 nm which is well suited with FESEM results, field emission scanning electron microscopy (FESEM) shows spherical, agglomerated particles with sizes ranging from 117 to 90 nm. The magnetic characteristics of the nanoparticles have been investigated through the application of a vibrating sample magnetometer (VSM). A reduction in saturation magnetization (Ms) is highlighted by the magnetic characterization from 68.18 emu/g to 48.55 emu/g, alongside an increasing coercivity (H_c) trend from 92.96 Oe to 109.06 Oe. Furthermore, the dielectric constant (<em>ε</em>′) decreases linearly at room temperature but rises with increasing temperature, indicating semiconducting behavior.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100273"},"PeriodicalIF":0.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The elementary particles as knots in the SU(2) higher homotopy Hopf group","authors":"Brian Jonathan Wolk","doi":"10.1016/j.physo.2025.100269","DOIUrl":"10.1016/j.physo.2025.100269","url":null,"abstract":"<div><div>Twelve of the fifteen prime knots with seven or less crossings taken as inclusions in the higher homotopic Hopf group of <span><math><mrow><mi>S</mi><mi>U</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span> are used to delineate and distinguish the twelve Standard Model quarks and leptons. These knot inclusions set the generational assignment of the quarks and leptons and permit the conjecture that knot hyperbolic volume hierarchy controls the physical mass hierarchy of the elementary particles. The hierarchy conjecture permits a postulate regarding the Yukawa couplings.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100269"},"PeriodicalIF":0.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights into structural and magnetic properties of manganite perovskite La0.7Ca0.3Mn0.6Co0.4O3 nanoparticles prepared by sol gel auto combustion route","authors":"R. Sharma ,&nbsp;P. Kumar ,&nbsp;Anil","doi":"10.1016/j.physo.2025.100272","DOIUrl":"10.1016/j.physo.2025.100272","url":null,"abstract":"<div><div>The calcium and cobalt co-doped Lanthanum Manganite (La_0.7Ca_0.3Mn_0.6Co_0.4O₃) polycrystalline ceramic was synthesized by sol-gel autocombustion route. The codoping strategy was adopted to study the synergistic effect of incorporating both Ca²⁺ and Mn³⁺ ions in the structural and magnetic properties of LaMnO₃ perovskite for technical applications. The as-prepared sample was characterized by XRD, SEM, FTIR and VSM. XRD study confirmed the formation of a single phase compound with an orthorhombic crystal structure having Pbnm space group. The lattice parameters obtained by reitveld refinements are: a = 5.4406 Å, b = 5.4921 Å and c = 7.7159 Å. The crystallite size was calculated from scherrer method, williamson hall plot, modified scherrer plot, size strain plot, halder wagner plot, reitveld method and compared. The diverse morphology was confirmed by FESEM analysis, while FTIR spectra shows presence of MnO₆ octahedra. Magnetic studies through VSM confirms antiferromagnetic behavior and moderate values of saturation magnetization and coercivity along with higher magnetocrystalline anisotropy, thus suggesting potential application in the field of magnetic sensors like AMR sensors and read heads of hard disk in magnetic data storage applications.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100272"},"PeriodicalIF":0.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the utility function of experiments in fundamental science","authors":"Tommaso Dorigo ,&nbsp;Michele Doro ,&nbsp;Max Aehle ,&nbsp;Muhammad Awais ,&nbsp;Nicolas R. Gauger ,&nbsp;Rafael Izbicki ,&nbsp;Jan Kieseler ,&nbsp;Ann B. Lee ,&nbsp;Luca Masserano ,&nbsp;Federico Nardi ,&nbsp;Alexander Shen ,&nbsp;Luis Recabarren Vergara","doi":"10.1016/j.physo.2025.100270","DOIUrl":"10.1016/j.physo.2025.100270","url":null,"abstract":"<div><div>The majority of experiments in fundamental science today are designed to be multi-purpose: their aim is not simply to measure a single physical quantity or process, but rather to enable increased precision in the measurement of a number of different observable quantities of a natural system, to extend the search for new phenomena, or to exclude a larger phase space of candidate theories. Most of the time, a combination of the above goals is pursued; this breadth of scope adds a layer of complexity to the already demanding task of designing the measurement apparatus in an optimal way, by defining suitable geometries and choosing the most advantageous materials and appropriate detection technologies. The precise definition of a global optimality criterion may then require experimentalists to find a consensus on the relative scientific worth of those goals.</div><div>In this work we discuss the problem of formulating a utility function for multipurpose experiments, as an enabling step to employ artificial intelligence tools to explore the design space and assist humans in finding solutions at the Pareto front. For that purpose, we consider two use cases in particle physics research and one in astro-particle physics; in the latter case we show, using a recently developed optimization software, how the precise definition of a multi-target utility function may enable a significant increase of its value above that offered by human-designed detector layouts.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100270"},"PeriodicalIF":0.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic Weyl semimetals as a source of circularly polarized THz radiation","authors":"Jeremy Hansen ,&nbsp;Kazuki Ikeda ,&nbsp;Dmitri E. Kharzeev ,&nbsp;Qiang Li ,&nbsp;Kirill Tuchin","doi":"10.1016/j.physo.2025.100268","DOIUrl":"10.1016/j.physo.2025.100268","url":null,"abstract":"<div><div>We propose to use the electromagnetic radiation induced by a few MeV electron beam in magnetic Weyl semimetals as a source of the circularly polarized photons in the THz frequency range.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100268"},"PeriodicalIF":0.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exchange bias study in FM/AFM bilayers: Atomistic simulations","authors":"Junaid Ul Ahsan","doi":"10.1016/j.physo.2025.100265","DOIUrl":"10.1016/j.physo.2025.100265","url":null,"abstract":"<div><div>The exchange bias (EB) effect has been studied through simulations utilizing the Landau–Lifshitz–Gilbert equation and the Heisenberg spin model in a Ferromagnet/Antiferromagnet bilayer system where the Antiferromagnet layer near the interface is modified by disturbing the AFM order. As an immediate effect of the disturbance of AFM order, the M-H loop of the bilayer broadens and also becomes asymmetric. Therefore the artificial heterostructure exhibits the bias field, suggesting a way to tune the exchange bias effect for scientific applications.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"23 ","pages":"Article 100265"},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}