Pub Date : 2025-12-13DOI: 10.1016/j.rinp.2025.108558
Shashikant Kumar, Gulshan Kumar, Prakash Parida
We investigate the optical conductivity of two-dimensional flat-band systems undergoing a transition from Lieb to kagome lattice geometries. Using a generalized tight-binding Hamiltonian with intrinsic spin–orbit coupling (ISOC), we compute both the real and imaginary parts of the longitudinal optical conductivity via the Kubo formula. At and fillings, we identify key differences in interband transitions between Dirac and flat bands across lattice geometries. In the Lieb lattice, Dirac-to-Dirac transitions are symmetry-forbidden, while Dirac-to-flat band transitions dominate. In contrast, the kagome lattice supports both Dirac-to-Dirac and Dirac-to-flat transitions, resulting in a broadened optical response that extends into the ultraviolet regime. ISOC opens non-trivial gaps at Dirac and points, enabling direct optical estimation of the ISOC-induced gap and enhancing transition strengths by factors up to two. Our results demonstrate how lattice geometry and ISOC jointly govern flat-band optical responses, with implications for tunable optoelectronic and plasmonic applications in two-dimensional kagome-based materials.
{"title":"Spin–orbit modulated optical properties in Lieb-to-kagome lattices","authors":"Shashikant Kumar, Gulshan Kumar, Prakash Parida","doi":"10.1016/j.rinp.2025.108558","DOIUrl":"10.1016/j.rinp.2025.108558","url":null,"abstract":"<div><div>We investigate the optical conductivity of two-dimensional flat-band systems undergoing a transition from Lieb to kagome lattice geometries. Using a generalized tight-binding Hamiltonian with intrinsic spin–orbit coupling (ISOC), we compute both the real and imaginary parts of the longitudinal optical conductivity via the Kubo formula. At <span><math><mrow><mn>1</mn><mo>/</mo><mn>3</mn></mrow></math></span> and <span><math><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></math></span> fillings, we identify key differences in interband transitions between Dirac and flat bands across lattice geometries. In the Lieb lattice, Dirac-to-Dirac transitions are symmetry-forbidden, while Dirac-to-flat band transitions dominate. In contrast, the kagome lattice supports both Dirac-to-Dirac and Dirac-to-flat transitions, resulting in a broadened optical response that extends into the ultraviolet regime. ISOC opens non-trivial gaps at Dirac and <span><math><mi>Γ</mi></math></span> points, enabling direct optical estimation of the ISOC-induced gap and enhancing transition strengths by factors up to two. Our results demonstrate how lattice geometry and ISOC jointly govern flat-band optical responses, with implications for tunable optoelectronic and plasmonic applications in two-dimensional kagome-based materials.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108558"},"PeriodicalIF":4.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.rinp.2025.108555
Huda Yahya Maky , Gholamreza Karimi , Fouad N. Ajeel
The thermoelectric properties of armchair graphene nanoribbons (AGNRs) have garnered significant interest due to their promising potential in energy conversion applications. However, achieving a balance between electrical conductance and thermal conductance remains a major challenge. In this study, we investigate the effects of double vacancy (DV) defects and chromium (Cr) doping on the thermoelectric performance of AGNRs using Extended Hückel theory (EHT) combined with nonequilibrium Green’s function (NEGF) formalism. Our results display that the introduction of DV defects reduces the bandgap of AGNRs, enhancing the carrier transport and creating thermally accessible electronic states. However, the most notable improvement occurs with Cr doping. Chromium atoms, introduced at various lattice sites within DV-defected AGNRs, significantly reduce the bandgap further, introduce mid-gap states, and increase electrical conductance. The interplay between Cr dopants and DV defects leads to a significant enhancement in Seebeck coefficient and a reduction in thermal conductance, resulting in improved thermoelectric performance. Specifically, a four-Cr atom configuration yields the highest thermoelectric figure of merit , reaching a value of 1.93 at room temperature. This performance is driven by the combined effects of reduced the thermal conductance, high electrical conductance, and a moderately enhanced Seebeck coefficient. Additionally, the study emphasizes the importance of dopant site engineering, as Cr placement at specific lattice sites maximizes the thermoelectric efficiency by enhancing carrier delocalization without introducing excessive metallic behavior. These findings suggest that the co-engineering of defects and dopants, particularly Cr doping, offers a promising strategy for enhancing the thermoelectric performance of AGNRs. This study paves the way for future design strategies in the development of high-performance, low-power thermoelectric materials for nanoscale energy harvesting applications.
{"title":"Tuning the properties of armchair graphene nanoribbons via chromium doping and double vacancy engineering","authors":"Huda Yahya Maky , Gholamreza Karimi , Fouad N. Ajeel","doi":"10.1016/j.rinp.2025.108555","DOIUrl":"10.1016/j.rinp.2025.108555","url":null,"abstract":"<div><div>The thermoelectric properties of armchair graphene nanoribbons (AGNRs) have garnered significant interest due to their promising potential in energy conversion applications. However, achieving a balance between electrical conductance and thermal conductance remains a major challenge. In this study, we investigate the effects of double vacancy (DV) defects and chromium (Cr) doping on the thermoelectric performance of AGNRs using Extended Hückel theory (EHT) combined with nonequilibrium Green’s function (NEGF) formalism. Our results display that the introduction of DV defects reduces the bandgap of AGNRs, enhancing the carrier transport and creating thermally accessible electronic states. However, the most notable improvement occurs with Cr doping. Chromium atoms, introduced at various lattice sites within DV-defected AGNRs, significantly reduce the bandgap further, introduce mid-gap states, and increase electrical conductance. The interplay between Cr dopants and DV defects leads to a significant enhancement in Seebeck coefficient and a reduction in thermal conductance, resulting in improved thermoelectric performance. Specifically, a four-Cr atom configuration yields the highest thermoelectric figure of merit <span><math><mrow><mi>ZT</mi></mrow></math></span>, reaching a value of 1.93 at room temperature. This performance is driven by the combined effects of reduced the thermal conductance, high electrical conductance, and a moderately enhanced Seebeck coefficient. Additionally, the study emphasizes the importance of dopant site engineering, as Cr placement at specific lattice sites maximizes the thermoelectric efficiency by enhancing carrier delocalization without introducing excessive metallic behavior. These findings suggest that the co-engineering of defects and dopants, particularly Cr doping, offers a promising strategy for enhancing the thermoelectric performance of AGNRs. This study paves the way for future design strategies in the development of high-performance, low-power thermoelectric materials for nanoscale energy harvesting applications.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108555"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the structural, superconducting, magneto-transport, and ultrafast optical properties of Bi2Se3-doped FeSe1-xTex single crystals containing 1 % (F37B1) and 4 % (F37B4) Bi2Se3. X-ray diffraction confirmed high crystallinity with c-axis-preferred orientation. The superconducting transition temperature increased from ∼ 10 K in F37B1 to ∼ 14 K in F37B4. Magneto-transport measurements revealed characteristic weak-antilocalization behavior and a clear violation of Kohler’s rule, consistent with enhanced spin–orbit scattering and multiband charge transport. X-ray photoelectron spectroscopy verified the chemical stability of Bi incorporation without secondary phases or oxidation. Magnetic hysteresis loops confirmed the presence of robust type-II superconductivity in both samples. Ultrafast optical spectroscopy revealed doping-dependent carrier relaxation: F37B1 showed faster decay components, while F37B4 exhibited slower recombination dynamics. These findings demonstrate that Bi2Se3 incorporation systematically modifies the electronic scattering environment in FeSe1-xTex. It also strengthens spin–orbit interactions. Together, these effects provide important insight into how dopants can tune the superconducting and dynamical properties of iron chalcogenides.
{"title":"Enhanced superconductivity and Spin-Orbit interaction in Bi2Se3-Doped FeSe1-xTex bulk single crystals","authors":"Ankush Saxena , Shiu-Ming Huang , Saurabh Saini , Chitimireddy Prashant , Chang-Yi Ou , Pin-Cing Wang , I-Yu Huang , Sanyam Jain , Rajiv Singh , Mitch Chou","doi":"10.1016/j.rinp.2025.108553","DOIUrl":"10.1016/j.rinp.2025.108553","url":null,"abstract":"<div><div>We investigated the structural, superconducting, magneto-transport, and ultrafast optical properties of Bi<sub>2</sub>Se<sub>3</sub>-doped FeSe<sub>1-x</sub>Te<sub>x</sub> single crystals containing 1 % (F37B1) and 4 % (F37B4) Bi<sub>2</sub>Se<sub>3</sub>. X-ray diffraction confirmed high crystallinity with c-axis-preferred orientation. The superconducting transition temperature increased from ∼ 10 K in F37B1 to ∼ 14 K in F37B4. Magneto-transport measurements revealed characteristic weak-antilocalization behavior and a clear violation of Kohler’s rule, consistent with enhanced spin–orbit scattering and multiband charge transport. X-ray photoelectron spectroscopy verified the chemical stability of Bi incorporation without secondary phases or oxidation. Magnetic hysteresis loops confirmed the presence of robust type-II superconductivity in both samples. Ultrafast optical spectroscopy revealed doping-dependent carrier relaxation: F37B1 showed faster decay components, while F37B4 exhibited slower recombination dynamics. These findings demonstrate that Bi<sub>2</sub>Se<sub>3</sub> incorporation systematically modifies the electronic scattering environment in FeSe<sub>1-x</sub>Te<sub>x</sub>. It also strengthens spin–orbit interactions. Together, these effects provide important insight into how dopants can tune the superconducting and dynamical properties of iron chalcogenides.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108553"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.rinp.2025.108554
Sabah E. Algarni , A.F. Qasrawi , Najla M. Khusayfan
Here, we investigate stacked amorphous-silicon (a-Si) layers embedding Fe nanosheets. While the Fe nanosheets do not perturb the amorphous matrix, we observe pronounced improvements in the optical and electronic responses: optical absorption, dielectric response, optical conductivity, and the terahertz cut-off frequency are all enhanced. Incorporation of Fe sheets increases the absorption by more than 100 %. The absorption enhancement, evaluated across multiple samples with associated error bars, reaches up to 832 % at 1.70 eV. Embedding Fe nanosheets narrows the optical band gap and raises the static dielectric constant by 64.5 %. The optical conductivity and terahertz cut-off frequency rise by more than 1000 % and ∼ 600 %, respectively. Drude–Lorentz analysis of the conductivity spectra indicates the feasibility of a-Si/Fe/a-Si stacks as terahertz band-pass filters, supporting carrier drift mobility up to 30.40 cm2 V−1 s−1. In addition, electrical measurements show an abrupt conductivity increase and a transition to metallic behavior. At microwave frequencies, the a-Si/Fe/a-Si interfaces exhibit GSM-1800 (1.8 GHz)/quad-band band-pass filter characteristics compatible with contemporary mobile-network deployments, and the filter design and performance are consistent with commercially available alternatives. Additionally, point antennas were designed and exhibited excellent performance, including up to 2.2 GHz matched bandwidth, Reflection parameter deeper than –30 dB, and isolation below –15 dB across the operating range (1 k-6.0 GHz).
{"title":"Enhanced dielectric dispersion, light absorption and optical conduction in a-Si/Fe/a-Si gigahertz/terahertz electro-optical band filters","authors":"Sabah E. Algarni , A.F. Qasrawi , Najla M. Khusayfan","doi":"10.1016/j.rinp.2025.108554","DOIUrl":"10.1016/j.rinp.2025.108554","url":null,"abstract":"<div><div>Here, we investigate stacked amorphous-silicon (a-Si) layers embedding Fe nanosheets. While the Fe nanosheets do not perturb the amorphous matrix, we observe pronounced improvements in the optical and electronic responses: optical absorption, dielectric response, optical conductivity, and the terahertz cut-off frequency are all enhanced. Incorporation of Fe sheets increases the absorption by more than 100 %. The absorption enhancement, evaluated across multiple samples with associated error bars, reaches up to 832 % at 1.70 eV. Embedding Fe nanosheets narrows the optical band gap and raises the static dielectric constant by 64.5 %. The optical conductivity and terahertz cut-off frequency rise by more than 1000 % and ∼ 600 %, respectively. Drude–Lorentz analysis of the conductivity spectra indicates the feasibility of a-Si/Fe/a-Si stacks as terahertz band-pass filters, supporting carrier drift mobility up to 30.40 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>. In addition, electrical measurements show an abrupt conductivity increase and a transition to metallic behavior. At microwave frequencies, the a-Si/Fe/a-Si interfaces exhibit GSM-1800 (1.8 GHz)/quad-band band-pass filter characteristics compatible with contemporary mobile-network deployments, and the filter design and performance are consistent with commercially available alternatives. Additionally, point antennas were designed and exhibited excellent performance, including up to 2.2 GHz matched bandwidth, Reflection parameter deeper than –30 dB, and isolation below –15 dB across the operating range (1 k-6.0 GHz).</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108554"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Negative Electron Affinity (NEA)-activated GaAs-based superlattice photocathodes remain the only source capable of generating spin-polarized electron beams with polarization exceeding 90%, making them indispensable for applications such as particle accelerators and spin-resolved spectroscopy. However, conventional Cs-O activation suffers from chemical instability, resulting in rapid degradation of quantum efficiency (QE) due to gas adsorption and ion back bombardment (IBB). To maintain high performance, operation under ultra-high vacuum conditions (<10−9 Pa) is required; however, the photocathode’s lifetime remains short. In our system, for example, multialkali photocathodes (e.g., K2CsSb) typically exhibit an operational lifetime of approximately 4000 h, while NEA-GaAs photocathodes degrade significantly faster, with a lifetime of only about 20 h. To overcome these limitations, NEA activation using heterojunctions with alkali metals and antimony (Sb) or tellurium (Te) has been proposed. In particular, a Cs-Sb-O activation scheme shows promise in improving both QE and lifetime. In this study, we systematically investigate the effects of substrate temperature, Sb thickness, and timing of Sb deposition on performance. We find that a 0.5 nm Sb layer yields a QE of approximately 2% at 780 nm-comparable to Cs-O activation-while extending the dark lifetime by a factor of 10. These results demonstrate the viability of the Cs-Sb-O scheme for stable, long-lived spin-polarized electron sources. These findings provide practical guidelines for the development of robust electron sources in accelerators.
{"title":"Systematic optimization of Cs-Sb-O activated NEA GaAs photocathodes for long-lived accelerator electron sources","authors":"Lei Guo , Yoshifumi Takashima , Masao Kuriki , Masahiro Yamamoto","doi":"10.1016/j.rinp.2025.108552","DOIUrl":"10.1016/j.rinp.2025.108552","url":null,"abstract":"<div><div>Negative Electron Affinity (NEA)-activated GaAs-based superlattice photocathodes remain the only source capable of generating spin-polarized electron beams with polarization exceeding 90%, making them indispensable for applications such as particle accelerators and spin-resolved spectroscopy. However, conventional Cs-O activation suffers from chemical instability, resulting in rapid degradation of quantum efficiency (QE) due to gas adsorption and ion back bombardment (IBB). To maintain high performance, operation under ultra-high vacuum conditions (<10<sup>−9</sup> Pa) is required; however, the photocathode’s lifetime remains short. In our system, for example, multialkali photocathodes (e.g., K<sub>2</sub>CsSb) typically exhibit an operational lifetime of approximately 4000 h, while NEA-GaAs photocathodes degrade significantly faster, with a lifetime of only about 20 h. To overcome these limitations, NEA activation using heterojunctions with alkali metals and antimony (Sb) or tellurium (Te) has been proposed. In particular, a Cs-Sb-O activation scheme shows promise in improving both QE and lifetime. In this study, we systematically investigate the effects of substrate temperature, Sb thickness, and timing of Sb deposition on performance. We find that a 0.5 nm Sb layer yields a QE of approximately 2% at 780 nm-comparable to Cs-O activation-while extending the dark lifetime by a factor of 10. These results demonstrate the viability of the Cs-Sb-O scheme for stable, long-lived spin-polarized electron sources. These findings provide practical guidelines for the development of robust electron sources in accelerators.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108552"},"PeriodicalIF":4.6,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.rinp.2025.108550
Qifeng Yan, Shuai Zhao, XiangJi Guo, Tao Chen, Ming Ming
A phase updating algorithm is proposed to design a diffractive optical element (DOE) to suppress the side-lobes of the Bessel-Gauss beam generated by the reflective off-axis axicon. Due to the tilt between the incident light and the outgoing light, conventional angular spectrum method (ASM)-based algorithm cannot be directly applied to the calculation of the off-axis Bessel-Gauss beam. To update the phase of the DOE, a novel algorithm is used where non-uniform inverse discrete Fourier transform is employed to calculate the off-axis diffraction. Only one iteration is required to obtain the specified Bessel-Gauss beam. For a Bessel-Gauss beam with a central peak diameter of 21.5 (9.8) μm, we demonstrate a DOE with the side-lobes energy lower than 0.8% and depth of focus (DOF) of 399.1 (100.7) μm, respectively.
{"title":"Design of diffractive optical elements to suppress the Bessel-Gauss beam generated by reflective off-axis axicon","authors":"Qifeng Yan, Shuai Zhao, XiangJi Guo, Tao Chen, Ming Ming","doi":"10.1016/j.rinp.2025.108550","DOIUrl":"10.1016/j.rinp.2025.108550","url":null,"abstract":"<div><div>A phase updating algorithm is proposed to design a diffractive optical element (DOE) to suppress the side-lobes of the Bessel-Gauss beam generated by the reflective off-axis axicon. Due to the tilt between the incident light and the outgoing light, conventional angular spectrum method (ASM)-based algorithm cannot be directly applied to the calculation of the off-axis Bessel-Gauss beam. To update the phase of the DOE, a novel algorithm is used where non-uniform inverse discrete Fourier transform is employed to calculate the off-axis diffraction. Only one iteration is required to obtain the specified Bessel-Gauss beam. For a Bessel-Gauss beam with a central peak diameter of 21.5 (9.8) μm, we demonstrate a DOE with the side-lobes energy lower than 0.8% and depth of focus (DOF) of 399.1 (100.7) μm, respectively.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108550"},"PeriodicalIF":4.6,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.rinp.2025.108551
Ban Khalid Mohammed , Babak Abdollahipour , Somayeh Oskoui Abdol
Weyl semimetals exhibit exceptional electronic and optical properties, positioning them as promising candidates for a wide range of applications. Notably, these materials naturally support surface waves in the infrared frequency range. In this study, we propose an optical biosensor operating in the near-infrared region, based on a combination of a one-dimensional photonic crystal and multiple layers of Weyl semimetal separated by a dielectric material. We evaluate the sensor’s performance using two diagnostic approaches: angle interrogation and wavelength interrogation techniques. Our results show that under angle interrogation, a biosensor comprising a single layer of Weyl semimetal achieves a notably high sensitivity of 160°/RIU and a figure of merit of 2486.48 RIU−1. Alternatively, when using the wavelength interrogation method, the biosensor with a single layer of Weyl semimetal delivers superior sensing performance, reaching a maximum sensitivity of 1050 nm/RIU and a figure of merit of 1035.14 RIU−1. These results highlight the potential of Weyl semimetal-based structures for high-performance biosensing in the near-infrared spectrum.
{"title":"Near-infrared biosensors based on optical Tamm plasmons in one-dimensional photonic crystal heterostructre containing Weyl semimetals","authors":"Ban Khalid Mohammed , Babak Abdollahipour , Somayeh Oskoui Abdol","doi":"10.1016/j.rinp.2025.108551","DOIUrl":"10.1016/j.rinp.2025.108551","url":null,"abstract":"<div><div>Weyl semimetals exhibit exceptional electronic and optical properties, positioning them as promising candidates for a wide range of applications. Notably, these materials naturally support surface waves in the infrared frequency range. In this study, we propose an optical biosensor operating in the near-infrared region, based on a combination of a one-dimensional photonic crystal and multiple layers of Weyl semimetal separated by a dielectric material. We evaluate the sensor’s performance using two diagnostic approaches: angle interrogation and wavelength interrogation techniques. Our results show that under angle interrogation, a biosensor comprising a single layer of Weyl semimetal achieves a notably high sensitivity of 160°/RIU and a figure of merit of 2486.48 RIU<sup>−1</sup>. Alternatively, when using the wavelength interrogation method, the biosensor with a single layer of Weyl semimetal delivers superior sensing performance, reaching a maximum sensitivity of 1050 nm/RIU and a figure of merit of 1035.14 RIU<sup>−1</sup>. These results highlight the potential of Weyl semimetal-based structures for high-performance biosensing in the near-infrared spectrum.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108551"},"PeriodicalIF":4.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.rinp.2025.108548
Dan Wang , Kaiwen Yao , Zhuoxi Lian , Guohe Zhang , Yang Li , Junlin Li , Ruibin Li
Secondary electron emission (SEE) is a crucial phenomenon in field of materials science, with significant applications in electron microscopes and electron multipliers. In this research, by utilizing a combination of standard electromagnetic physics models and customized parameters, the Geant4 framework is employed to model the SEE process, which achieves the Monte Carlo simulation of SEE yield (SEY) across various materials and surface conditions. The main processes of the modelling includes inelastic scattering, elastic scattering, and interfacial transmission, are tailored to improve the accuracy of SEE simulations. The study evaluates the impact of different parameters such as cut-off energy (Ec) and surface barrier energy loss (EL) on the simulation results. With appropriate parameters, the simulation results for MgO agree well with experimental data. By normalizing the simulation results and experimental data, the two can be better matched. In the low energy of primary electrons (Ep) range of 0 < Ep/Em < 1.5, the calculated results are consistent with the experimental results with a difference less than 0.2. Additionally, the simulations are further applied to 7 materials (Al, Si, C, MgO, Al2O3, SiO2, TiN) and 3 surface conditions (incident angle, nanofilm coatings and microstructures) as application examples. The average difference between calculated maximum SEY and measured maximal SEY is less than 10 %. This Monte Carlo model is an extensible platform for SEY calculation and can provide help in the application of SEY prediction and modulation in electronic devices involving the SEE process.
{"title":"Secondary electron emission calculation based on correcting electron scattering models achieved by Monte Carlo simulation in Geant4","authors":"Dan Wang , Kaiwen Yao , Zhuoxi Lian , Guohe Zhang , Yang Li , Junlin Li , Ruibin Li","doi":"10.1016/j.rinp.2025.108548","DOIUrl":"10.1016/j.rinp.2025.108548","url":null,"abstract":"<div><div>Secondary electron emission (SEE) is a crucial phenomenon in field of materials science, with significant applications in electron microscopes and electron multipliers. In this research, by utilizing a combination of standard electromagnetic physics models and customized parameters, the Geant4 framework is employed to model the SEE process, which achieves the Monte Carlo simulation of SEE yield (SEY) across various materials and surface conditions. The main processes of the modelling includes inelastic scattering, elastic scattering, and interfacial transmission, are tailored to improve the accuracy of SEE simulations. The study evaluates the impact of different parameters such as cut-off energy (<em>E</em><sub>c</sub>) and surface barrier energy loss (<em>E</em><sub>L</sub>) on the simulation results. With appropriate parameters, the simulation results for MgO agree well with experimental data. By normalizing the simulation results and experimental data, the two can be better matched. In the low energy of primary electrons (<em>E</em><sub>p</sub>) range of 0 < <em>E</em><sub>p</sub>/<em>E</em><sub>m</sub> < 1.5, the calculated results are consistent with the experimental results with a difference less than 0.2. Additionally, the simulations are further applied to 7 materials (Al, Si, C, MgO, Al<sub>2</sub>O<sub>3</sub>, SiO<sub>2</sub>, TiN) and 3 surface conditions (incident angle, nanofilm coatings and microstructures) as application examples. The average difference between calculated maximum SEY and measured maximal SEY is less than 10 %. This Monte Carlo model is an extensible platform for SEY calculation and can provide help in the application of SEY prediction and modulation in electronic devices involving the SEE process.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108548"},"PeriodicalIF":4.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two-dimensional (2D) materials with engineered electronic correlations are emerging as versatile platforms for next-generation optoelectronics. Here we present a comprehensive theoretical investigation of the electronic and optical properties of a C3N monolayer using a tight-binding framework combined with the Hubbard Hamiltonian and Green’s function formalism. We show that electron–electron interactions, mechanical strain, and carrier doping act as powerful tuning parameters that reshape the optical response. Coulomb correlations drive notable modifications in the density of states (DOS), giving rise to semi-metallic behavior under specific regimes. Optical conductivity calculations reveal a prominent absorption feature near 4 eV, which undergoes systematic blue shifts and intensity modulation upon electron doping, reflecting Fermi-level–controlled interband transitions. External strain further tailors both the spectral position and strength of optical excitations, establishing strain engineering as an effective control knob. Transmission and reflectivity spectra indicate broadband opacity of C3N, underscoring its potential for reflective coatings and nanoscale energy-control applications. Our results provide fundamental insights into the interplay of correlations, strain, and doping in 2D C3N, and establish design principles for tailoring its optoelectronic functionality in advanced device technologies.
{"title":"Tunable optoelectronic properties of C3N monolayers via correlation, strain, and doping","authors":"Soleimani Maryam, Astinchap Bander, Abdi Mona, Alemipour Zahra","doi":"10.1016/j.rinp.2025.108547","DOIUrl":"10.1016/j.rinp.2025.108547","url":null,"abstract":"<div><div>Two-dimensional (2D) materials with engineered electronic correlations are emerging as versatile platforms for next-generation optoelectronics. Here we present a comprehensive theoretical investigation of the electronic and optical properties of a C<sub>3</sub>N monolayer using a tight-binding framework combined with the Hubbard Hamiltonian and Green’s function formalism. We show that electron–electron interactions, mechanical strain, and carrier doping act as powerful tuning parameters that reshape the optical response. Coulomb correlations drive notable modifications in the density of states (DOS), giving rise to semi-metallic behavior under specific regimes. Optical conductivity calculations reveal a prominent absorption feature near 4 eV, which undergoes systematic blue shifts and intensity modulation upon electron doping, reflecting Fermi-level–controlled interband transitions. External strain further tailors both the spectral position and strength of optical excitations, establishing strain engineering as an effective control knob. Transmission and reflectivity spectra indicate broadband opacity of C<sub>3</sub>N, underscoring its potential for reflective coatings and nanoscale energy-control applications. Our results provide fundamental insights into the interplay of correlations, strain, and doping in 2D C<sub>3</sub>N, and establish design principles for tailoring its optoelectronic functionality in advanced device technologies.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108547"},"PeriodicalIF":4.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.rinp.2025.108546
G. Nandhini, M.K. Shobana
The synergistic exploration of magnetic nanoparticles and bioactive plant extracts has yielded a groundbreaking cancer therapeutic modality, capitalizing on the potential of nanotechnology and phytochemistry to target and ablate malignant cells. This comprehensive investigation elucidates the impact of various plant extracts on the structural, magnetic, hyperthermic, and cytotoxic properties of MnFe2O4 nanoparticles. The structural analysis of the nanoparticles functionalized with plant extracts reveals the formation of a single-phase spinel structure and exhibits a spherical morphology. FTIR analysis confirms the incorporation of bioactive compounds by identifying specific functional groups that contribute to the stabilization and functionalization of the nanoparticles. The microscopic and macroscopic investigation of magnetic properties exhibits a high saturation magnetization of 47 emu/g, accompanied by an inherently low coercivity (∼14 Oe) and a relatively short transverse relaxation time of 3.18*10-11 s. Below the biological threshold, Zingiber officinale extract with MnFe2O4 nanoparticles exhibits a high specific absorption rate of 329 W/g under an applied magnetic field. The cytotoxicity analysis of Allium sativum extract revealed a good selectivity index of 2.3 with a 37 μg/ml IC50 value, illustrating anti-proliferation activity against A-549 cells. These findings highlight the importance of phytochemical functionalization in MnFe2O4 nanoparticle performance for magnetic hyperthermia applications, with potential implications for cancer treatment.
{"title":"Effect of Phytochemical-Mediated synthesis using Allium sativum, Zingiber officinale, and Carica papaya extracts on the Inductive heating characteristics of MnFe2O4 nanoparticles","authors":"G. Nandhini, M.K. Shobana","doi":"10.1016/j.rinp.2025.108546","DOIUrl":"10.1016/j.rinp.2025.108546","url":null,"abstract":"<div><div>The synergistic exploration of magnetic nanoparticles and bioactive plant extracts has yielded a groundbreaking cancer therapeutic modality, capitalizing on the potential of nanotechnology and phytochemistry to target and ablate malignant cells. This comprehensive investigation elucidates the impact of various plant extracts on the structural, magnetic, hyperthermic, and cytotoxic properties of MnFe<sub>2</sub>O<sub>4</sub> nanoparticles. The structural analysis of the nanoparticles functionalized with plant extracts reveals the formation of a single-phase spinel structure and exhibits a spherical morphology. FTIR analysis confirms the incorporation of bioactive compounds by identifying specific functional groups that contribute to the stabilization and functionalization of the nanoparticles. The microscopic and macroscopic investigation of magnetic properties exhibits a high saturation magnetization of 47 emu/g, accompanied by an inherently low coercivity (∼14 Oe) and a relatively short transverse relaxation time of 3.18*10<sup>-11</sup> s. Below the biological threshold, <em>Zingiber officinale</em> extract with MnFe<sub>2</sub>O<sub>4</sub> nanoparticles exhibits a high specific absorption rate of 329 W/g under an applied magnetic field. The cytotoxicity analysis of <em>Allium sativum</em> extract revealed a good selectivity index of 2.3 with a 37 μg/ml IC<sub>50</sub> value, illustrating anti-proliferation activity against A-549 cells. These findings highlight the importance of phytochemical functionalization in MnFe<sub>2</sub>O<sub>4</sub> nanoparticle performance for magnetic hyperthermia applications, with potential implications for cancer treatment.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"80 ","pages":"Article 108546"},"PeriodicalIF":4.6,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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