检索结果-内蒙古大学图书馆

Exceptional features in nonlinear Hermitian systems

Physical Review B 2025年第16期111卷 L161102-L161102页

作者： Liang Fang Kai Bai Cheng Guo Tian-Rui Liu Jia-Zheng Li Meng Xiao Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan University Wuhan China Ginzton Laboratory and Department of Electrical Engineering Stanford University Stanford California 94305 USA Wuhan Institute of Quantum Technology Wuhan 430206 China

Non-Hermitian systems and their topological singularities, such as exceptional points (EPs), lines, and surfaces, have recently attracted intense interest. The investigation of these exceptional constituents has led to fruitful applications. The responsivity of the eigenvalue diverges at EPs, and chiral state transfer occurs when encircling an EP. Traditionally, it was believed that these exceptional features were unique to non-Hermitian systems requiring gain, loss, or nonreciprocal hopping. Here we show that these exceptional features are also present in nonlinear Hermitian systems. We consider two coupled resonators with Kerr nonlinearity in one resonator, and no non-Hermitian terms. We identify EP-like points (ELPs) on the eigenspectra where the critical behaviors are the same as those of typical EPs. Additionally, this nonlinear Hermitian system can be mapped to linear non-Hermitian systems, with ELPs corresponding to EPs. We also demonstrate that encirclement around an ELP in the parameter space leads to unique chiral state transfer behavior.

关键词： Topology

来源：评论

学校读者我要写书评

暂无评论

Flat-band based high-temperature ferromagnetic semiconducting state in the graphitic C_(4)N_(3) monolayer

引用

Fundamental Research 2025年第1期5卷 138-144页

作者： Chaoyu He Yujie Liao Tao Ouyang Huimin Zhang Hongjun Xiang Jianxin Zhong Laboratory for Quantum Engineering and Micro-Nano Energy Technology and School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China Key Laboratory of Computational Physical Sciences(Ministry of Education) Institute of Computational Physical SciencesDepartment of PhysicsFudan UniversityShanghai 200433China

Half-filled isolated flat-band paves a new way to realize high-temperature ferromagnetic semiconductor for spintronics applications,but it is extremely rare in lattice models and lacking in realistic ***,the 2×2 super-cell of the honeycomb lattice with a single-hole defect is proposed as a new lattice model(HL-D-1/8)to realize nontrivial isolated *** further demonstrate that C_(4)N_(3)monolayer of the experimentally realized graphitic carbon nitride(***.,22,1004,2010;***.,9,3366,2018)is a perfect system holding such a lattice to host flat-bands.A new corrugated Pca21 configuration is proposed as the ground state for the free-standing C_(4)N_(3)monolayer,which is dynamically stable and energetically more favorable than the widely-used flat one without dynamical *** Pca21 configuration is found to be an intrinsic ferromagnetic half-semiconductor(T_(c)≈241 K)with one semiconducting spin-channel(1.75 eV)and one insulating spin-channel(3.64 eV),which is quite rare in two-dimensional *** ferromagnetic semiconducting property originates from the isolated pz-state flat-band as the corrugation shifts the flat-band upward to the Fermi ***,such a corrugated Pca21 C_(4)N_(3)monolayer is found to be both piezoelectric and ferroelectric,which makes it an unusual metal-free two-dimensional multiferroic.

关键词： Graphitic C_(4)N_(3) Isolated flat-band Ferromagnetic semiconductor Two-dimensional multiferroic First-principles calculation Tight-binding model

来源：评论

学校读者我要写书评

暂无评论

Combining intrinsic and sliding-induced polarizations for multistates in two-dimensional ferroelectrics

引用

Physical Review B 2025年第8期111卷 L081407-L081407页

作者： Chuhan Tang Zhiqiang Tian Tao Ouyang Anlian Pan Mingxing Chen Key Laboratory for Matter Microstructure and Function of Hunan Province Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education School of Physics and Electronics Hunan Normal University Changsha 410081 China Hunan Key Laboratory for Micro-Nano Energy Materials and Device and School of Physics and Optoelectronics Xiangtan University Hunan Xiangtan 411105 China Key Laboratory for Micro-Nano Physics and Technology of Hunan Province College of Materials Science and Engineering Hunan University Changsha 410082 China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China

Going beyond the bistability paradigm of the charge polarization in ferroelectrics is highly desired for ferroelectric (FE) memory devices toward ultrahigh-density information storage. Here, we propose to build multistates by combining the intrinsic and sliding-induced polarizations. The physics is that there is at least one order of magnitude difference in the energy barriers between these two types of polarizations, which leads to a significant difference in the electric fields for reversing the polarization. This difference, along with the symmetry breaking, allows for a unique flipping mechanism involving layer-by-layer sliding followed by layer-by-layer flipping during the transformation of the multistates. As a result, six and ten switchable states can be achieved for the 1T″ bilayers and trilayers, respectively. We further illustrate the concept in H-stacking bilayers and trilayers of 1T″ transition-metal dichalcogenides by first-principles calculations. Our study provides a route to design polarization multistates for developing next-generation memory devices.

关键词： Ferroelectricity

来源：评论

学校读者我要写书评

暂无评论

Higher-order topology in twisted multilayer systems:A review

引用

Chinese physics B 2025年第3期34卷 2-10页

作者： Chunbo Hua Dong-Hui Xu Key Laboratory of Artificial Micro-and Nanostructures of Ministry of Education and School of Physics and Technology Wuhan UniversityWuhan 430072China School of Electronic and Information Engineering Hubei University of Science and TechnologyXianning 437100China Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics Chongqing UniversityChongqing 400044China Center of Quantum Materials and Devices Chongqing UniversityChongqing 400044China

In recent years,there has been a surge of interest in higher-order topological phases(HOTPs)across various disciplines within the field of *** unique phases are characterized by their ability to harbor topological protected boundary states at lower-dimensional boundaries,a distinguishing feature that sets them apart from conventional topological phases and is attributed to the higher-order bulk-boundary ***-dimensional(2D)twisted systems offer an optimal platform for investigating HOTPs,owing to their strong controllability and experimental ***,we provide a comprehensive overview of the latest research advancements on HOTPs in 2D twisted multilayer *** will mainly review the HOTPs in electronic,magnonic,acoustic,photonic and mechanical twisted systems,and finally provide a perspective of this topic.

关键词： higher-order topology twisted multilayer systems van der Waals materials corner states

来源：评论

学校读者我要写书评

暂无评论

Improving performance of perovskite solar cells enabled by defects passivation and carrier transport dynamics regulation via organic additive

引用

Chinese Chemical Letters 2025年第2期36卷 523-528页

作者： Rongjun Zhao Tai Wu Yong Hua Yude Wang Department of Physics Center for Optoelectronics Engineering ResearchYunnan UniversityKunming 650091China Yunnan Key Laboratory for Micro/Nano Materials&Technology International Joint Research Center for Optoelectronic and Energy MaterialsSchool of Materials and EnergyYunnan UniversityKunming 650091China Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies Yunnan UniversityKunming 6500504China

Defects at the grain boundaries(GBs)of perovskite film highly restrict both the efficiency and stability of perovskite solar cells(PSCs).Herein,organic small molecules of butanedioic acid(BA)and acetylenedicarboxylic acid(AA),containing two carbonyl(C=O)groups and different core-units,were incorporated into perovskite as additives for PSCs *** to the strong coordination interaction between C=O group and under-coordinated Pb^(2+),the additives can effectively passivate film defects and regulate the perovskite crystallization,yielding high-quality perovskite films with lower defect *** importantly,the additives can efficiently regulate the charge transport behaviors in *** from the defects passivation and the regulation of charge carrier dynamics,the BA and AA-treaded PSCs show the power conversion efficiencies of 21.52%and 20.50%,which are higher than that of the control device(19.41%).Besides,the optimal devices exhibit a remarkable enhanced long-term stability and moisture tolerance compared to the pristine ***,the transient absorption spectrum reveals the mechanism of enhanced photovoltaic performances,attributing to the improvement of charge transport capability at the perovskite/Spiro-OMeTAD *** work affords a promising strategy to improve the efficiency and stability of PSCs through regulating the charge-carrier dynamic process in perovskite film.

关键词： Perovskite solar cells Additives Defects passivation Carrier dynamics Stability

来源：评论

学校读者我要写书评

暂无评论

Aegis of oxide passivation stabilizes catalytic methanol steam reforming

引用

Science China Chemistry 2025年第6期68卷 2215-2216页

作者： Han Yan Jie Zeng Hefei National Research Center for Physical Sciences at the Microscale Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of Sciences Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesDepartment of Chemical Physics University of Science and Technology of China School of Chemistry & Chemical Engineering Anhui University of Technology

Hydrogen energy is very likely to benefit the next generation of technology, owing to its unparalleled energy efficiency,intrinsic clean nature, and renewable properties [1]. With the application of the photovoltaic industry and water electrolysis, H2production with near-zero greenhouse gas emissions becomes feasible. At present, the key obstacle to the large-scale and safe application of H2fuel lies in its transportation and storage. Herein, developing inexpensive liquid H2storage media, such as methanol or ammonia, and the relevant catalytic techniques are of vital significance [2].

关键词：

来源：评论

学校读者我要写书评

暂无评论

Antibacterial Properties of Carbon Fiber/Polyether Ether Ketone Artificial Bone Composites Modified by Black Phosphorus Coating Assisted by Wet Chemical Nitration Surface Treatment

引用

Journal of Bionic engineering 2025年第2期22卷 838-850页

作者： Luxiao Sang Hao Li Runze Shi Wen Qin Tong Xing Shengnan Qin Aoqun Jian Shanxi Key Laboratory of Micro Nano Sensors and Artificial Intelligence Perception College of Physics and Optoelectronic EngineeringTaiyuan University of TechnologyTaiyuan030024China Department of Materials Science and Engineering Shanxi Institute of TechnologyYangquan045000China The Fifth Clinical Medical College of Shanxi Medical University Shanxi Provincial People’s HospitalTaiyuan030012China

The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the Two-Dimensional (2D) nanomaterials with unique lamellar structures and biological properties have been demonstrated to have excellent antibacterial properties. Antibacterial properties can be improved by feasible chemical strategies for preparing 2D nanomaterials coating on the surface of CFR-P. In this work, Black Phosphorus (BP) coating was prepared on the originally chemically inert CFR-P surface based on wet chemical pretreatment. The physical and chemical properties, including surface microstructure, chemical composition and state, roughness and hydrophilicity were characterized. The antibacterial ratios against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Streptococcus mutans (S. mutans) were evaluated. The results indicated that hydrophilicity of BP coating on CFR-P was significantly higher compared to that of the pure CFR-P. Wet chemical pretreatment using mixed acid reagents (concentrated sulfuric acid and concentrated nitric acid) introduced hydroxyl, carboxyl and nitro groups on CFR-P. The BP coating exhibited the antibacterial rate of over 98% against both S. aureus and E. coli. In addition, the antibacterial rate of BP coating against the main pathogenic bacteria of dental caries, Streptococcus mutans, reached 45%.

关键词： Carbon fiber reinforced peek composites Surface modification Black phosphorus microstructure Antibacterial property

来源：评论

学校读者我要写书评

暂无评论

Axial coordinated iron-nitrogen-carbon as efficient electrocatalysts for hydrogen evolution and oxygen redox reactions

引用

Chinese Chemical Letters 2025年第1期36卷 637-642页

作者： Yanan Zhou Li Sheng Lanlan Chen Wenhua Zhang Jinlong Yang School of Material Science and Chemical Engineering Institute of Mass SpectrometryNingbo UniversityNingbo 315211China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Department of Material Science and Engineering University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion and Synergetic Innovation Centre of Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaHefei 230026China

Designing highly active electrocatalysts for the hydrogen evolution reaction(HER)and oxygen evolution and reduction reactions(OER and ORR)is pivotal to renewable energy ***,based on density functional theory(DFT)calculations,we systematically investigate the catalytic activity of iron-nitrogen-carbon based covalent organic frameworks(COF)monolayers with axially coordinated ligands(denotes as Fe N_(4)-X@COF,X refers to axial ligand,X=-SCN,-I,-H,-SH,-NO_(2),-Br,-ClO,-Cl,-HCO_(3),-NO,-ClO_(2),-OH,-CN and-F).The calculated results demonstrate that all the catalysts possess good thermodynamic and electrochemical *** different ligands axially ligated to the Fe active center could induce changes in the charge of the Fe center,which further regulates the interaction strength between intermediates and catalysts that governs the catalytic ***,FeN_(4)-SH@COF and Fe N_(4)-OH@COF are efficient bifunctional catalysts for HER and OER,FeN_(4)-OH@COF and FeN_(4)-I@COF are promising bifunctional catalysts for OER and *** findings not only reveal promising bifunctional HER/OER and OER/ORR catalysts but also provide theoretical guidance for designing optimum ironnitrogen-carbon based catalysts.

关键词： Axial coordinated ligands DFT calculation Hydrogen evolution reaction Oxygen evolution reaction Oxygen reduction reaction

来源：评论

学校读者我要写书评

暂无评论

C3N/BN heterostructure: A promising anode material in lithium-ion batteries

引用

Applied physics Letters 2025年第17期126卷

作者： Peng, Yan Tang, Xu You, Manqi Guo, Gencai Guo, Gang Luo, Siwei Zhong, Jianxin Hunan Key Laboratory for Micro-Nano Energy Materials and Devices Laboratory for Quantum Engineering and Micro-Nano Energy Technology School of Physics and Optoelectronics Xiangtan University Hunan411105 China Institute for Quantum Science and Technology Shanghai University Shanghai200444 China School of Science Hunan Institute of Technology Hengyang421002 China

In the in-depth study of anode materials for lithium-ion batteries, C3N has become the focus of attention due to its high stiffness and good electrical conductivity. However, its limited lithium mobility restricts its practical application. In contrast, BN offers excellent thermal stability and lithium mobility but has poor conductivity. This study combines the strengths of both materials by constructing a C3N/BN heterostructure. Calculated results show the heterostructure exhibits excellent mechanical properties, with a Young's modulus of 632.0 N m−1. Moreover, the adsorption energy of Li in the C3N/BN heterostructure (0.98 eV) is greatly enhanced compared to that in monolayer C3N (0.54 eV) and BN (0.03 eV), and the capacity can reach 1276.56 mA h g−1. Due to the influence of BN, Li migration energy barrier is reduced to 0.26 eV, lower than that of monolayer C3N (0.34 eV). Besides, the heterostructure also shows favorable wettability in common electrolytes. These results highlight the C3N/BN heterostructure as a promising anode candidate for high-performance lithium-ion batteries. © 2025 Author(s).

关键词： Lithium-ion batteries

来源：评论

学校读者我要写书评

暂无评论

Inorganic Additives Induce More Small-Sized microplastics Releasing from Medical Face Masks

引用

Environmental Science and technology 2025年第18期59卷 2025 Apr 28页

作者： Wang, Licheng Xie, Lifang Li, Yumo Huang, Tingting You, Wenbo Tahir, Muhammad Ali Wang, Wei Ge, Qiuyue Liu, Yangyang Wang, Tao Wang, Longqian Ruan, Xuejun Ji, Minbiao Zhang, Liwu Department of Environmental Science & Engineering Fudan University Shanghai200433 China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Fudan University Shanghai200433 China Shanghai Institute of Pollution Control and Ecological Security Shanghai200092 China State Key Laboratory of Surface Physics Department of Physics Academy for Engineering and Technology Key Laboratory of Micro and Nano Photonic Structures Ministry of Education Fudan University Shanghai200433 China

Although previous studies have extensively explored the release of microplastics from masks, the specific influence of inorganic additives on microplastic emissions has remained unidentified. Herein, we performed a comparative analysis of medical face masks (MFMs) with calcium carbonate (CaCO3) additives against those devoid of CaCO3 to understand their roles in microplastic release. Briefly, our investigation employed surface-enhanced Raman spectroscopy (SERS) to examine micro- and nanoplastic release, while the stereoscopic characterization of mixing states of additives in microplastic was accomplished through a simulated Raman scattering (SRS). We also pioneered a three-dimensional imaging (3D imaging) method for investigating the internal aging of plastic using SRS, which clearly revealed the link between inorganic additives inside polymers and photoaging. We found that inorganic additives substantially accelerate the photoaging of the plastic materials through multiple pathways and induce more small-sized microplastics. Follow-up radical quenching experiments confirmed carbonate radicals as the main cause of this phenomenon. Our research exposes the hazardous potential of inorganic additives in masks to amplify the emission of microplastics. © 2025 American Chemical Society.

关键词： Stimulated Raman scattering

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：