Previous investigations have typically employed metal FeSiCr powders with large average particle sizes to prepare the magnetic powder cores (SMCs), with few studies reporting on the influence of magnetic properties for original powders with various average particle sizes less than 10 μm. In this work, the SiO2-coated FeSiCr SMCs with different small particle sizes were synthesized using the sol-gel process. The contribution of SiO2 coating amount and voids to the soft magnetic properties was elaborated. The mechanism was revealed by that smaller particle sizes with less voids could be beneficial for reducing core loss in the SMCs. By optimizing the core structure, permeability and magnetic loss of 26 and 262 kW/cm3 at 100 kHz and 50 mT were achieved at a particle size of 4.8 μm and ethyl orthosilicate addition of 0.1 mL/g, respectively. The best DC stacking performance, reaching 87%, was observed at an ethyl orthosilicate addition rate of 0.25 mL/g under 100 Oe. Compared to other soft magnetic composites (SMCs), the FeSiCr/SiO2 SMCs exhibited significantly reduced magnetic loss. It further reduces the magnetic loss of the powder core, providing a new strategy for the application of SMCs at high frequencies.
{"title":"Enhanced soft magnetic properties of SiO2-coated FeSiCr magnetic powder cores by particle size effect","authors":"Mingyue Ge, Likang Xiao, Xiaoru Liu, Lin Pan, Zhangyang Zhou, Jianghe Lan, Zhengwei Xiong, Jichuan Wu, Zhipeng Gao","doi":"10.1088/1674-1056/ad6556","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6556","url":null,"abstract":"\u0000 Previous investigations have typically employed metal FeSiCr powders with large average particle sizes to prepare the magnetic powder cores (SMCs), with few studies reporting on the influence of magnetic properties for original powders with various average particle sizes less than 10 μm. In this work, the SiO2-coated FeSiCr SMCs with different small particle sizes were synthesized using the sol-gel process. The contribution of SiO2 coating amount and voids to the soft magnetic properties was elaborated. The mechanism was revealed by that smaller particle sizes with less voids could be beneficial for reducing core loss in the SMCs. By optimizing the core structure, permeability and magnetic loss of 26 and 262 kW/cm3 at 100 kHz and 50 mT were achieved at a particle size of 4.8 μm and ethyl orthosilicate addition of 0.1 mL/g, respectively. The best DC stacking performance, reaching 87%, was observed at an ethyl orthosilicate addition rate of 0.25 mL/g under 100 Oe. Compared to other soft magnetic composites (SMCs), the FeSiCr/SiO2 SMCs exhibited significantly reduced magnetic loss. It further reduces the magnetic loss of the powder core, providing a new strategy for the application of SMCs at high frequencies.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823005","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}
Pub Date : 2024-07-19DOI: 10.1088/1674-1056/ad655a
Guangdi Zhang, Li Mao, Hongxing Xu
In real space Density Functional Theory calculations, the effective potential depends on the electron density, requiring self-consistent iterations and numerous integrals at each step, making the process timeconsuming. In our research, we propose an optimization method to expedite Density Functional Theory calculations for systems with large aspect ratios, such as metallic nanorods, nanowires, or Scanning Tunneling Microscope tips. This method focuses on employing basis set to expand the electron density, Coulomb potential, and exchange-correlation potential. By precomputing integrals and caching redundant results, this expansion streamlines the integration process, significantly accelerating Density Functional Theory computations. As a case study, we have applied this optimization to metallic nanorod systems of various radii and lengths, obtaining corresponding ground-state electron densities and potentials.
{"title":"Optimized numerical Density Functional Theory calculation of rotationally symmetric jellium model systems","authors":"Guangdi Zhang, Li Mao, Hongxing Xu","doi":"10.1088/1674-1056/ad655a","DOIUrl":"https://doi.org/10.1088/1674-1056/ad655a","url":null,"abstract":"\u0000 In real space Density Functional Theory calculations, the effective potential depends on the electron density, requiring self-consistent iterations and numerous integrals at each step, making the process timeconsuming. In our research, we propose an optimization method to expedite Density Functional Theory calculations for systems with large aspect ratios, such as metallic nanorods, nanowires, or Scanning Tunneling Microscope tips. This method focuses on employing basis set to expand the electron density, Coulomb potential, and exchange-correlation potential. By precomputing integrals and caching redundant results, this expansion streamlines the integration process, significantly accelerating Density Functional Theory computations. As a case study, we have applied this optimization to metallic nanorod systems of various radii and lengths, obtaining corresponding ground-state electron densities and potentials.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 465","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823578","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}
Pub Date : 2024-07-19DOI: 10.1088/1674-1056/ad6557
Fengbo Han, Jiaxin Gu, Lu Huang, Hang Wang, Yali Huang, Xuecheng Zhou, Shaoliang Yu, Zhengqian Luo, Zhipeng Dong, Qingyang Du
The increasing demand in spectroscopy and sensing calls for mid-IR light sources. Here, we theoretically investigate nonlinear wavelength conversion of Ge28Sb12Se60 chalcogenide glass waveguide in the mid-IR spectral regime. With waveguide dispersion engineering, we predict generation of over an octave wavelength (2.8~5.9 μm) tuning range Raman soliton self-frequency shift, over 2.5 octaves wavelength cover range supercontinuum (1.2~8.0 μm), as well as single soliton Kerr comb generated in suspended Ge28Sb12Se60 waveguide. Our findings evidenced that Ge28Sb12Se60 chalcogenide glass waveguides can simultaneously satisfy the generation of Raman soliton self frequency shift, supercontinuum spectrum, and Kerr frequency comb generation through dispersion engineering towards mid-IR on chip.
{"title":"Third-Order Nonlinear Wavelength Conversion in Chalcogenide Glass Waveguides towards Mid-Infrared Photonics","authors":"Fengbo Han, Jiaxin Gu, Lu Huang, Hang Wang, Yali Huang, Xuecheng Zhou, Shaoliang Yu, Zhengqian Luo, Zhipeng Dong, Qingyang Du","doi":"10.1088/1674-1056/ad6557","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6557","url":null,"abstract":"\u0000 The increasing demand in spectroscopy and sensing calls for mid-IR light sources. Here, we theoretically investigate nonlinear wavelength conversion of Ge28Sb12Se60 chalcogenide glass waveguide in the mid-IR spectral regime. With waveguide dispersion engineering, we predict generation of over an octave wavelength (2.8~5.9 μm) tuning range Raman soliton self-frequency shift, over 2.5 octaves wavelength cover range supercontinuum (1.2~8.0 μm), as well as single soliton Kerr comb generated in suspended Ge28Sb12Se60 waveguide. Our findings evidenced that Ge28Sb12Se60 chalcogenide glass waveguides can simultaneously satisfy the generation of Raman soliton self frequency shift, supercontinuum spectrum, and Kerr frequency comb generation through dispersion engineering towards mid-IR on chip.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 1183","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823461","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}
We present a formalism of charge self-consistent dynamical mean field theory (DMFT) in combination with density functional theory (DFT) within the linear combination of numerical atomic orbitals (LCNAO) framework. We implemented the charge self-consistent DFT+DMFT formalism by interfacing a full-potential all-electron DFT code with three hybridization expansion-based continuous-time quantum Monte Carlo impurity solvers. The benchmarks on several 3d, 4f and 5f strongly correlated electron systems validated our formalism and implementation. Furthermore, within the LCANO framework, our formalism is general and the code architecture is extensible, so it can work as a bridge merging different LCNAO DFT packages and impurity solvers to do charge self-consistent DFT+DMFT calculations.
{"title":"Charge Self-consistent Dynamical Mean Field Theory Calculations in Combination with Linear Combination of Numerical Atomic Orbitals Framework based Density Functional Theory","authors":"Xin Qu, Peng Xu, Zhiyong Liu, Jintao Wang, Fei Wang, Wei Huang, Zhongxin Li, Weichang Xu, Xinguo Ren","doi":"10.1088/1674-1056/ad6558","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6558","url":null,"abstract":"\u0000 We present a formalism of charge self-consistent dynamical mean field theory (DMFT) in combination with density functional theory (DFT) within the linear combination of numerical atomic orbitals (LCNAO) framework. We implemented the charge self-consistent DFT+DMFT formalism by interfacing a full-potential all-electron DFT code with three hybridization expansion-based continuous-time quantum Monte Carlo impurity solvers. The benchmarks on several 3d, 4f and 5f strongly correlated electron systems validated our formalism and implementation. Furthermore, within the LCANO framework, our formalism is general and the code architecture is extensible, so it can work as a bridge merging different LCNAO DFT packages and impurity solvers to do charge self-consistent DFT+DMFT calculations.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":"110 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821484","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}
Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications. However, a significant challenge arises from the fixed shapes of nanostructures post-fabrication, resulting in limited modes under ordinary illumination. A promising solution lies in far-field control facilitated by spatial light modulators (SLMs), which enable on-site, real-time, and non-destructive manipulation of plasmon excitation. Through the robust modulation of incident light using SLMs, this approach enables the generation, optimization, and dynamic control of surface plasmon polariton (SPP) and localized surface plasmon (LSP) modes. The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy, offering novel approaches for signal optimization and functional expansion in this field. This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.
{"title":"Light-field modulation and optimization near metal nanostructures utilizing spatial light modulators","authors":"Zini Cao, Hai Lin, Yuqing Cheng, Yixuan Xu, Qihuang Gong, Guowei Lü","doi":"10.1088/1674-1056/ad6555","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6555","url":null,"abstract":"\u0000 Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications. However, a significant challenge arises from the fixed shapes of nanostructures post-fabrication, resulting in limited modes under ordinary illumination. A promising solution lies in far-field control facilitated by spatial light modulators (SLMs), which enable on-site, real-time, and non-destructive manipulation of plasmon excitation. Through the robust modulation of incident light using SLMs, this approach enables the generation, optimization, and dynamic control of surface plasmon polariton (SPP) and localized surface plasmon (LSP) modes. The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy, offering novel approaches for signal optimization and functional expansion in this field. This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 778","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823392","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}
Pub Date : 2024-07-19DOI: 10.1088/1674-1056/ad6554
Yang Sun, Ruoshui Liu, H. Gong, Baogen Shen
Ion substitution has significantly improved the performance of ferrite magnets, with cobalt remaining a key area of research. Studies on the mechanism of Co2+ in strontium ferrite, especially SrFe2n-x Co x O19-δ (n=6.1-5.4, x=0.05-0.20) synthesized using the ceramic method, showed that Co2+ preferentially enters the lattice as Fe/Sr ratio decreases. This results in a decrease in lattice constants a and c due to oxygen vacancies and iron ion deficiency. The impact of Co-substitution on morphology is minor compared to the effect of the Fe/Sr ratio. As the Fe/Sr ratio decreases and Co content increases, saturation magnetization decreases. The magnetic anisotropy field exhibits a nonlinear change, generally increasing with higher Fe/Sr ratios and Co content. These changes in the performance of permanent magnets are attributed to the absence of Fe3+ ions at the 12k+2a and 2b sites and the substitution of Co2+ at 2b site. This suggests that by adjusting the Fe/Sr ratio and appropriate Co substitution, the magnetic anisotropy field of M-type strontium ferrite can be effectively optimized.
离子置换大大提高了铁氧体磁体的性能，而钴仍然是一个关键的研究领域。对锶铁氧体，特别是用陶瓷法合成的 SrFe2n-x Co x O19-δ（n=6.1-5.4，x=0.05-0.20）中 Co2+ 的机理研究表明，随着铁/锶比的降低，Co2+ 会优先进入晶格。由于氧空位和铁离子缺乏，这导致晶格常数 a 和 c 下降。与铁/锶比的影响相比，钴替代对形态的影响较小。随着铁/锶比的降低和钴含量的增加，饱和磁化会降低。磁各向异性场呈现非线性变化，一般随着铁/锶比和钴含量的增加而增加。永磁体性能的这些变化归因于 12k+2a 和 2b 位点缺少 Fe3+ 离子以及 2b 位点的 Co2+ 替代。这表明，通过调整铁/锶比和适当的 Co 取代，可以有效优化 M 型锶铁氧体的磁各向异性场。
{"title":"Impact of Co2+ substitution on structure and magnetic properties of strontium ferrite with different Fe/Sr ratios","authors":"Yang Sun, Ruoshui Liu, H. Gong, Baogen Shen","doi":"10.1088/1674-1056/ad6554","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6554","url":null,"abstract":"\u0000 Ion substitution has significantly improved the performance of ferrite magnets, with cobalt remaining a key area of research. Studies on the mechanism of Co2+ in strontium ferrite, especially SrFe2n-x\u0000 Co\u0000 x\u0000 O19-δ\u0000 (n=6.1-5.4, x=0.05-0.20) synthesized using the ceramic method, showed that Co2+ preferentially enters the lattice as Fe/Sr ratio decreases. This results in a decrease in lattice constants a and c due to oxygen vacancies and iron ion deficiency. The impact of Co-substitution on morphology is minor compared to the effect of the Fe/Sr ratio. As the Fe/Sr ratio decreases and Co content increases, saturation magnetization decreases. The magnetic anisotropy field exhibits a nonlinear change, generally increasing with higher Fe/Sr ratios and Co content. These changes in the performance of permanent magnets are attributed to the absence of Fe3+ ions at the 12k+2a and 2b sites and the substitution of Co2+ at 2b site. This suggests that by adjusting the Fe/Sr ratio and appropriate Co substitution, the magnetic anisotropy field of M-type strontium ferrite can be effectively optimized.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":"9 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822355","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}
Pub Date : 2024-07-19DOI: 10.1088/1674-1056/ad655b
Yizhou Tao, Chao Liu, Mingwen Xiao, Henan Fang
We have investigated the peak structure in the interlayer conductance of moiré superlattices using a tunneling theory developed previously by us. The theoretical results predict that, due to the resonance of two different partial waves, the double-peak structure can appear in the curve of the interlayer conductance versus twist angle. Furthermore, we have studied the influences of the model parameters, i.e. the chemical potential of electrodes, the thickness of moiré superlattice and the strength of interface potential, on the peak structure of the interlayer conductance. In particular, the parameter dependence of the peak structure is concluded via a phase diagram, and the physical meanings of the phase diagram is formulized. Finally, the potential applications of the present work is discussed.
{"title":"Peak Structure in the Interlayer Conductance of Moiré Superlattices","authors":"Yizhou Tao, Chao Liu, Mingwen Xiao, Henan Fang","doi":"10.1088/1674-1056/ad655b","DOIUrl":"https://doi.org/10.1088/1674-1056/ad655b","url":null,"abstract":"\u0000 We have investigated the peak structure in the interlayer conductance of moiré superlattices using a tunneling theory developed previously by us. The theoretical results predict that, due to the resonance of two different partial waves, the double-peak structure can appear in the curve of the interlayer conductance versus twist angle. Furthermore, we have studied the influences of the model parameters, i.e. the chemical potential of electrodes, the thickness of moiré superlattice and the strength of interface potential, on the peak structure of the interlayer conductance. In particular, the parameter dependence of the peak structure is concluded via a phase diagram, and the physical meanings of the phase diagram is formulized. Finally, the potential applications of the present work is discussed.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 1253","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822833","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}
Pub Date : 2024-07-17DOI: 10.1088/1674-1056/ad641e
L. Hou, Lei Shi, Liping Yang, Yiqiang Liu, Zhitao Li, Lanxiang Meng
To insight into the B-site ordering in RFe0.5Cr0.5O3 ceramics, a series of RFe0.5Cr0.5O3 ceramics (R = La, Y, Lu) were synthesized by the sol-gel method, and the structural and magnetic properties were systemically investigated. By using the Rietveld refinement of all samples, it is found that the structural distortion is increased as the R ionic radius decreases, leading to the weakened interactions between Fe/Cr ions. Besides, the Fe and Cr are arranged in disorder in LaFe0.5Cr0.5O3, but partially ordered in YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3, showing an increasing trend of the proportion of ordered domains with the decrease of R ionic radius. Through fitting the temperature-dependent magnetizations, it is identified that the magnetization reversal (MR) in disorder LaFe0.5Cr0.5O3 is resulted from the competition between the moments of Cr and Fe sublattices. In the partially ordered YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3 ceramics, because of the presence of Fe-O-Cr networks in the ordered domains whose moment is antiparallel to that of Fe-O-Fe and Cr-O-Cr in the disordered domains, the compensation temperature Tcomp of MR is increased by nearly 50 K. These results suggest that the changing of R-site ions could be used very effectively to modify the Fe-O-Cr ordering, apart from the structural distortion, which has a direct effect on the magnetic exchange interactions in RFe0.5Cr0.5O3 ceramics. Then at values of composition where ordered domains are expected to be larger in number as compared to disordered domains and with a weaker structural distortion, one can expect a higher transition temperature Tcomp, providing a different view for adjustment of the magnetic properties of RFe0.5Cr0.5O3 ceramics for practical applications.
{"title":"The B-site ordering in RFe0.5Cr0.5O3 ceramics and its effect on magnetic properties","authors":"L. Hou, Lei Shi, Liping Yang, Yiqiang Liu, Zhitao Li, Lanxiang Meng","doi":"10.1088/1674-1056/ad641e","DOIUrl":"https://doi.org/10.1088/1674-1056/ad641e","url":null,"abstract":"\u0000 To insight into the B-site ordering in RFe0.5Cr0.5O3 ceramics, a series of RFe0.5Cr0.5O3 ceramics (R = La, Y, Lu) were synthesized by the sol-gel method, and the structural and magnetic properties were systemically investigated. By using the Rietveld refinement of all samples, it is found that the structural distortion is increased as the R ionic radius decreases, leading to the weakened interactions between Fe/Cr ions. Besides, the Fe and Cr are arranged in disorder in LaFe0.5Cr0.5O3, but partially ordered in YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3, showing an increasing trend of the proportion of ordered domains with the decrease of R ionic radius. Through fitting the temperature-dependent magnetizations, it is identified that the magnetization reversal (MR) in disorder LaFe0.5Cr0.5O3 is resulted from the competition between the moments of Cr and Fe sublattices. In the partially ordered YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3 ceramics, because of the presence of Fe-O-Cr networks in the ordered domains whose moment is antiparallel to that of Fe-O-Fe and Cr-O-Cr in the disordered domains, the compensation temperature Tcomp of MR is increased by nearly 50 K. These results suggest that the changing of R-site ions could be used very effectively to modify the Fe-O-Cr ordering, apart from the structural distortion, which has a direct effect on the magnetic exchange interactions in RFe0.5Cr0.5O3 ceramics. Then at values of composition where ordered domains are expected to be larger in number as compared to disordered domains and with a weaker structural distortion, one can expect a higher transition temperature Tcomp, providing a different view for adjustment of the magnetic properties of RFe0.5Cr0.5O3 ceramics for practical applications.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141830745","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}
Minimizing disorder and defects is crucial for realizing the full potential of two-dimensional transition metal dichalcogenides (TMDs) materials and improving device performance to desired properties. However, the methods in defect control currently face challenges with overly large operational areas and lack of precision in targeting specific defects. Therefore, we propose a new method for the precise and universal defect healing of TMD materials, integrating real-time imaging with scanning transmission electron microscopy (STEM). This method employs electron beam irradiation to stimulate the diffusion migration of surface-adsorbed adatoms on TMD materials grown by low-temperature molecular beam epitaxy (MBE), and heal defects within the diffusion range. This approach covers defect repairs ranging from zero-dimensional vacancy defects to two-dimensional grain orientation alignment, demonstrating its universality in terms of the types of samples and defects. These findings offer insights into the use of atomic-level focused electron beams at appropriate voltages in STEM for defect healing, providing valuable experience for achieving atomic-level precise fabrication of TMD materials.
{"title":"Atomically Self-Healing of Structural Defects in Monolayer WSe2","authors":"Kangshu Li, Junxian Li, Xiaocang Han, Wu Zhou, Xiaoxu Zhao","doi":"10.1088/1674-1056/ad641f","DOIUrl":"https://doi.org/10.1088/1674-1056/ad641f","url":null,"abstract":"\u0000 Minimizing disorder and defects is crucial for realizing the full potential of two-dimensional transition metal dichalcogenides (TMDs) materials and improving device performance to desired properties. However, the methods in defect control currently face challenges with overly large operational areas and lack of precision in targeting specific defects. Therefore, we propose a new method for the precise and universal defect healing of TMD materials, integrating real-time imaging with scanning transmission electron microscopy (STEM). This method employs electron beam irradiation to stimulate the diffusion migration of surface-adsorbed adatoms on TMD materials grown by low-temperature molecular beam epitaxy (MBE), and heal defects within the diffusion range. This approach covers defect repairs ranging from zero-dimensional vacancy defects to two-dimensional grain orientation alignment, demonstrating its universality in terms of the types of samples and defects. These findings offer insights into the use of atomic-level focused electron beams at appropriate voltages in STEM for defect healing, providing valuable experience for achieving atomic-level precise fabrication of TMD materials.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141829484","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}
In this work the geometric structure parameters and radial density distribution of 1s2s 1 S excited state of the two-electron atomic system near the critical nuclear charge Z c were calculated in detail under tripled Hylleraas basis set. Contrary to the localized behavior observed in the ground and the doubly excited 2p 2 3 P e states, for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system, the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z c. This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.
在这项研究中，我们在三倍海勒拉斯（Hylleraas）基集下详细计算了临界核电荷 Z c 附近双电子原子系统 1s2s 1 S 激发态的几何结构参数和径向密度分布。与在基态和双激发态 2p 2 3 P e 中观察到的局部行为相反，我们的研究结果表明，虽然内层电子的行为越来越像类氢原子体系，但激发态中的外层电子却表现出扩散的类氢特征，并随着核电荷 Z 接近 Z c 而变得与内层电子垂直。
{"title":"Geometric properties of the first singlet S-wave excited state of two-electron atoms near the critical nuclear charge","authors":"Tong Chen, Sanjiang Yang, Wanping Zhou, Xue-Song Mei, Haoxue Qiao","doi":"10.1088/1674-1056/ad6422","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6422","url":null,"abstract":"\u0000 In this work the geometric structure parameters and radial density distribution of 1s2s\u0000 1\u0000 S excited state of the two-electron atomic system near the critical nuclear charge Z\u0000 c were calculated in detail under tripled Hylleraas basis set. Contrary to the localized behavior observed in the ground and the doubly excited 2p\u0000 2\u0000 3\u0000 P\u0000 e states, for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system, the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z\u0000 c. This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.","PeriodicalId":504421,"journal":{"name":"Chinese Physics B","volume":" 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141831338","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}
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