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Observation of double-kink states in multivalley acoustic crystals

Physical Review B 2024年第5期109卷 054109-054109页

作者： Xiao-Hui Gou Hua-Shan Lai Xiao-Chen Sun Si-Yuan Yu Y. B. Chen Cheng He Yan-Feng Chen National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering Nanjing University Nanjing 210093 China School of Physics Nanjing University Nanjing 210093 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China Jiangsu Key Laboratory of Artificial Functional Materials Nanjing University Nanjing 210093 China

The Dirac degeneracy of band structures, along with the valley states after breaking, holds promising potential for robust signal processing. However, the conventional graphene structure only harbors a single pair of Dirac points, limiting its capacity for information storage and manipulation, and hindering its application in small-sized on-chip devices. In this study, we experimentally investigate S-graphene acoustic crystals that host two pairs of Dirac points and valleys. By examining the interplay between these multivalley pairs, we observe double-kink edge states that display W-type and M-type dispersions self-guiding at zigzag- and bearded boundaries in a single sample, respectively, eliminating the requirement of a cladding layer in conventional valley Hall effect. Additionally, benefiting from the increased degree of freedom, a superdirectional yet adjustable topological antenna is demonstrated by selectively exciting a specific valley branch. This research expands the degree of freedom for valleytronics and has the potential to stimulate the exploration of multiple spin-valley couplings and the design of unique functional devices.

关键词： Edge states Topological insulators Valley degrees of freedom Acoustic metamaterials Acoustic techniques Band structure methods Finite-element method Tight-binding model

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Topological phase transition of photonic Chern insulators by multi-Mie-resonance inversion

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Physical Review Applied 2024年第5期21卷 054034-054034页

作者： Hui Huang Junzheng Hu Xiaofei Ye Shiqi Li Haotian Li Yao Jiang Minghui Lu Peng Zhan National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China School of Physics Nanjing University Nanjing 210093 China Department of Materials Science and Engineering Nanjing University Nanjing 210093 China Jiangsu Key Laboratory of Artificial Functional Materials Nanjing University Nanjing 210093 China

The atomic orbital, as an intrinsic degree of freedom, is critical in improving band-tailoring tactics in condensed-matter physics. In photonics, analogously to atomic orbitals, multiple Mie resonances provide an effective way for photonic band engineering. In this work, we demonstrate the topological phase transitions in photonic Chern insulators imposed by band topology through multiple Mie resonances. By continuously adjusting geometric parameters and the external magnetic field in a two-dimensional gyromagnetic photonic crystal, we present the inversion of Mie resonances together with alterations in the Chern number for the corresponding photonic band. Furthermore, we propose a hetero–photonic structure that combines photonic lattices with distinct Chern numbers and exhibits chiral edge states at the heterointerface. A simple magnetic regulation approach is also provided for effective control of the edge state’s on–off switching. Our work establishes a correlation between the band topology of photonic Chern insulators and Mie resonances, contributing to advancements in higher-band-topology research.

关键词： Chern insulators Edge states Magneto-optics Mie scattering Topological effects in photonic systems Topological insulators Topological phase transition Photonic crystals

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利用电荷转移工程提高红色SrLa(Sc,Ga)O_(4):Ce^(3+)荧光粉的热稳定性

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science China materials 2023年第5期66卷 1989-1996页

作者：杨至雨赵逸飞 Jumpei Ueda Maxim S.Molokeev 尚蒙蒙夏志国 State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied TechniquesGuangdong Engineering Technology Research and Development Centre of Special Optical Fibre Materials and DevicesSchool of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510641China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong 999077China Graduate School of Advanced Science and Technology Japan Advanced Institute of Science and Technology(JAIST)NomiIshikawa 923–1292Japan Laboratory of Crystal Physics Kirensky Institute of PhysicsFederal Research Center KSC SB RASKrasnoyarsk 660036Russia Department of Engineering Physics and Radioelectronic Siberian Federal UniversityKrasnoyarsk660041Russia Research and Development Department Kemerovo State UniversityKemerovo 650000Russia Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

可被蓝光激发的高热稳定性红色荧光粉是制作高性能白光二极管(WLED)的关键材料.研究发现,Ce^(3+)掺杂的SrLaScO_(4)(SLO:Ce^(3+))荧光粉在440 nm激发下呈现峰值为640 nm的反常宽带红光发射.光谱学和结构分析证实Ce^(3+)离子在SLO中进入[... 详细信息

可被蓝光激发的高热稳定性红色荧光粉是制作高性能白光二极管(WLED)的关键材料.研究发现,Ce^(3+)掺杂的SrLaScO_(4)(SLO:Ce^(3+))荧光粉在440 nm激发下呈现峰值为640 nm的反常宽带红光发射.光谱学和结构分析证实Ce^(3+)离子在SLO中进入[LaO_(8)]多面体,产生强的晶体场劈裂和较大的Stokes位移,实现了比Eu^(2+)更低能量的红光发射.我们还设计并揭示了一种电荷转移相互作用的策略:在Sc^(3+)位置引入电负性较大的Ga^(3+),Ga^(3+)可以吸引更多邻位配合基团的电荷,以减少导带底部的电子占用而扩大带隙.Sc/Ga取代有效地抑制了热激活电离过程,使SrLa(Sc,Ga)O_(4):Ce^(3+)的热稳定性获得了显著提升,即在150℃的发光强度比(相对于20℃)从15%提升至31%.本研究为发现具有良好热稳定性的新型Ce^(3+)掺杂红色荧光粉提供了有效的设计原则.

关键词： Ce^(3+) thermal stability band gap broadband red luminescence

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Skyrmion Molecule Lattices Enabling Stable Transport and Flexible Manipulation

arXiv

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arXiv 2025年

作者： Liu, Lei Zhang, Xiujuan Lu, Ming-Hui Chen, Yan-Feng National Laboratory of Solid State Microstructures Department of Materials Science and Engineering Nanjing University Nanjing210093 China Jiangsu Key Laboratory of Artificial Functional Materials Nanjing210093 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China

Skyrmions—topologically protected nanoscale spin textures with vortex-like configurations—hold transformative potential for ultra-dense data storage, spintronics and quantum computing. However, their practical utility is challenged by dynamic instability, complex interaction, and the lack of deterministic control. While recent efforts using classical wave systems have enabled skyrmion simulations via engineered excitations, these realizations rely on fragile interference patterns, precluding stable transport and flexible control. Here, we introduce a skyrmion molecule lattice, a novel architecture where pairs of spin skyrmions with opposite polarizability are symmetry-locked into stable molecule configurations. These molecules emerge as propagating eigenstates of the system, overcoming the static limitations of previous realizations. We further develop a boundary engineering technique, achieving precise control over skyrmion creation, deformation, annihilation, and polarizability inversion. As a proof of concept, we design a graphene-like acoustic surface wave metamaterial, where meta-atom pairs generate vortices with opposite orbital angular momenta, which couple to acoustic spin textures, forming skyrmion molecules. Experimental measurements confirm their stable transport and flexible control. Our work leverages the symmetry-locked molecule lattice to preserve the topological quasiparticle nature of skyrmions, offering a universal framework for their stabilization, transportation and manipulation. This bridges critical gaps in skyrmion physics, with potential impacts on wave-based sensing, information processing, and topological waveguiding. © 2025, CC BY.

关键词： Crystal lattices

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Large electro-opto-mechanical coupling in VO2 neuristors

arXiv

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arXiv 2023年

作者： Khandelwal, Upanya Sandilya, Rama Satya Rai, Rajeev Kumar Sharma, Deepak Mahapatra, Smruti Rekha Mondal, Debasish Bhat, Navakanta Aetkuri, Naga Phani Avasthi, Sushobhan Chandorkar, Saurabh Nukala, Pavan Center for Nanoscience and Engineering Indian Institute of Science Karnataka Bengaluru560012 India Materials Science and Engineering University of Pennsylvania 3231 Walnut Street Philadelphia19104 United States Solid State and Structural Chemistry Unit Indian Institute of Science Karnataka Bengaluru560012 India

Biological neurons are electro-mechanical systems, where the generation and propagation of an action potential is coupled to generation and transmission of an acoustic wave. Neuristors, such as VO2, characterized by insulator-metal transition (IMT) and negative differential resistance, can be engineered as self-oscillators, which are good approximations of biological neurons in the domain of electrical signals. In this study, we show that these self-oscillators are coupled electro-opto-mechanical systems, with better energy conversion coefficients than the conventional electromechanical or electrooptical materials. This is due to the significant contrast in the material’s resistance, optical refractive index and density across the induced temperature range in a Joule heating driven IMT. We carried out laser interferometry to measure the opto-mechanical response while simultaneously driving the devices electrically into self-oscillations of different kinds. We analyzed films of various thicknesses, engineered device geometry and performed analytical modelling to decouple the effects of refractive index change vis-à-vis mechanical strain in the interferometry signal. We show that the effective piezoelectric coefficient (d13*) for our neuristor devices is 660+20 pm/V, making them viable alternatives to Pb-based piezoelectrics for MEMS applications. Furthermore, we show that the effective electro-optic coefficient (r13*) is ~22 nm/V, which is much larger than that in thin-film and bulk Pockels materials. © 2023, CC BY.

关键词： Vanadium dioxide

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Anomalous Hall and Nernst effect and thermoelectric performance of Sb-doped MnBi6Te10

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Physical Review materials 2025年第1期9卷 015403-015403页

作者： Xinmeng Hu Takayoshi Katase Masaki Kondo Noriaki Hanasaki Hideaki Sakai Jiazhen Wu Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 China MDX Research Center for Element Strategy International Research Frontiers Initiative Tokyo Institute of Technology 4259 Nagatsuta Midori Yokohama 226–8501 Japan Department of Physics Osaka University Toyonaka Osaka 560-0043 Japan Present address: The Institute of Solid State Physics The University of Tokyo Kashiwa Chiba 277–8581 Japan. Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and Technology Shenzhen 518055 China Institute of Innovative Materials Southern University of Science and Technology Shenzhen 518055 China

Mn(Sb/Bi)2nTe3n+1, a well-known family of intrinsic magnetic topological insulator, possesses nontrivial topological electronic structures, making this family an excellent platform to investigate exotic quantum phenomena. These materials are closely related to the well-known thermoelectric material Bi2Te3. Particularly, with the introduction of intrinsic magnetism, energy conversion based on the magnetothermoelectric effect has also attracted researcher's attentions. Here, we study the magnetic, electrical, and thermoelectric transport properties of a 39% Sb-doped ferromagnetic MnBi6Te10 single crystal. Upon Sb doping, the carrier density is suppressed, the electrical resistivity exhibits a semiconducting behavior, and the power factor PF and the figure of merit ZT are estimated to be 5.07µWcm−1K−2 and 0.14, respectively, at 300 K. At low temperatures, the sample displays the characteristics of two-carriers transport as indicated by the nonlinear Hall effect. The spontaneous anomalous Hall effect and anomalous Nernst effect are observed below the Curie temperature TC∼13K. The Nernst thermopower versus magnetization, |Syx|/M, exceeds the scaling law of conventional magnets, highlighting the enhanced anomalous Nernst effect arising from the intrinsic contribution of the net Berry curvature. Our results provide experimental evidence of nontrivial electronic structures in the ferromagnetic Mn(Sb/Bi)6Te10 and highlight its potential for thermoelectric applications.

关键词： Ferromagnetism

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A trace of Pt can significantly boost RuO_(2) for acidic water splitting

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Chinese Journal of Catalysis 2022年第6期43卷 1493-1501页

作者： Qing Yao Jiabo Le Shize Yang Jun Cheng Qi Shao Xiaoqing Huang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123JiangsuChina Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201ZhejiangChina Eyring Materials Center Arizona State UniversityTempeArizonaUSA State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005FujianChina

The development of highly potential electrocatalysts for acidic water electrolysis is particularly desirable for many energy‐related ***,we demonstrated a versatile strategy to activate and stabilize RuO_(2)‐based electrocatalyst for acidic water splitting by a trace of Pt,where Pt plays an essential role in promoting oxygen evolution reaction(OER),and can simultaneously act as the active site for hydrogen evolution reaction(HER).Compared with pure Ru oxide nanosheet assemblies(Ru ONAs),the“5%Pt‐containing”Ru ONAs(5%Pt‐Ru ONAs)achieve much enhanced OER activity in 0.5 and 0.05 mol/L H_(2)SO_(4),with much lower overpotentials of 227 and 234 mV at 10 mA cm^(‒2),*** and theoretical analyses reveal that the atomically dispersed Pt incorporating into RuO_(2)lattice is conducive to increasing the concentration of O vacancies,which effectively enhances the interaction with reaction intermediate and thus lowers the energy barrier for the formation of OOH*.Moreover,benefited from the presence of Pt,the formation of RuO_(2)is more achievable when proper annealing is *** addition to OER,due to the presence of active Pt,the HER performance of 5%Pt‐Ru ONAs can also be ensured,thereby realizing efficient acidic overall water ***,the excellent activity can also be achieved without sacrificing *** work highlights an attractive strategy for designing active and stable RuO_(2)‐based electrocatalysts for acidic overall water splitting.

关键词： Ruthenium Platinum Oxygen vacancy Acidic Water splitting

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Self‑Generated Buried Submicrocavities for High‑Performance Near‑Infrared Perovskite Light‑Emitting Diode

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Nano-Micro Letters 2023年第8期15卷 355-367页

作者： Jiong Li Chenghao Duan Qianpeng Zhang Chang Chen Qiaoyun Wen Minchao Qin Christopher C.S.Chan Shibing Zou Jianwu Wei Zuo Xiao Chuantian Zuo Xinhui Lu Kam Sing Wong Zhiyong Fan Keyou Yan School of Environment and Energy State Key Lab of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Solid Wastes Pollution Control and RecyclingSouth China University of TechnologyGuangzhou 510000People’s Republic of China Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongPeople’s Republic of China Department of Physics The Chinese University of Hong KongShatinHong KongPeople’s Republic of China Department of Physics The Hong Kong University of Science and TechnologyClear Water BayKowloon 999077Hong KongPeople’s Republic of China School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004People’s Republic of China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190People’s Republic of China

ABSTRACT Embedding submicrocavities is an effective approach to improve the light out-coupling efficiency(LOCE)for planar perovskite light-emitting diodes(PeLEDs).In this work,we employ phenethylammonium iodide(PEAI)to trigger the Ostwald ripening for the downward recrystallization of perovskite,resulting in spontaneous formation of buried submicrocavities as light output *** simulation suggests the buried submicrocavities can improve the LOCE from 26.8 to 36.2%for near-infrared ***,PeLED yields peak external quantum efficiency(EQE)increasing from 17.3%at current density of 114 mA cm^(−2)to 25.5%at current density of 109 mA cm^(−2)and a radiance increasing from 109 to 487 W sr^(−1)m^(−2)with low *** turn-on voltage decreased from 1.25 to 1.15 V at 0.1 W sr^(−1)m^(−2).Besides,downward recrystallization process slightly reduces the trap density from 8.90×10^(15)to 7.27×10^(15)cm^(−3).This work provides a self-assembly method to integrate buried output coupler for boosting the performance of PeLEDs.

关键词： Perovskite light-emitting diodes Downward recrystallization Buried submicrocavities Light out-coupling efficiency Radiative recombination

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Study on the Removal and Adsorption Kinetics of Malachite Green in Water by Nay Molecular Sieve Prepared from Coal Gangue

SSRN

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SSRN 2024年

作者： Wang, Qingping Min, Jing Xu, Wei School of Materials Science and Engineering Anhui University of Science and Technology Huainan232001 China Anhui Industrial Generic Technology Research Center for New Materials from Coal-Based Solid Wastes Anhui University of Science and Technology Huainan232001 China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology Huainan232001 China

In order to make full use of silica-aluminum components in coal gangue, molecular sieves were synthesized from coal gangue by means of high temperature sintering and alkali solution hydrothermal method without stencil and additives. By studying the optimum synthesis conditions, NaY molecular sieve porous materials with specific mesoporous surface area of 621m2/g, average pore size of 4.69nm and pore volume of 0.21cm3/g was prepared. It has octahedral zeolite crystal structure, and has good adsorption properties for malachite green. Quasi-first-order kinetic model, quasi-second-order kinetic model and Weber Morris diffusion model were used to fit the adsorption kinetic data and adsorption equilibrium data, respectively. The results show that the adsorption of MG is mainly chemisorption, but there is also a secondary performance of physical adsorption. © 2024, The Authors. All rights reserved.

关键词： Adsorption

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Effect of Zr-deoxidation on microstructure and mechanical behavior of microalloyed heavy plates with low impurity content

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Journal of Iron and Steel Research International 2021年第2期28卷 190-200页

作者： Cheng-yang Hu Hang-yu Dong Kai-ming Wu R.D.K.Misra Lei Zhong Xing Jin Qiang Li Laboratory for Excellence in Advanced Steel Research Materials Science and Engineering ProgramDepartment of MetallurgicalMaterials and Biomedical EngineeringUniversity of Texas at El PasoEl Paso 79968TXUSA The State Key Laboratory of Refractories and Metallurgy International Research Institute for Steel TechnologyCollaborative Innovation Center for Advanced SteelsWuhan University of Science and TechnologyWuhan 430081HubeiChina Research Institute of Nanjing Iron and Steel Co. Ltd.Nanjing 210035JiangsuChina

The significance of different deoxidation practises on the ductility and impact toughness of next generation of microalloyed heavy plates was elucidated to explore the best deoxidation practice in obtaining required mechanical properties,which was judged by the combined effects of composition,size and number density of inclusions on the ductility of the experimental high-strength low alloy *** impurity contents,i.e.,total O+N+S contents,of 82×10^(-6)(Al-killed)and 118×10^(-6)(Zr-killed)have been induced to characterize both the *** was characterized using tensile and Charpy V-notch *** number,size and composition of the inclusions were characterized using a field emission scanning electron microscope with an energy dispersive *** the Al-killed steel,the inclusion structure consisted of titanium nitrides,stringer calcium aluminates and elongated manganese sulfides,whereas in the Zr-killed steel,the inclusion structure consisted of mainly fine spherical oxide inclusions with sulphide *** impurity content did not have a significant effect on the number density of inclusions,as with higher and lower impurity content,the number of inclusions was 83.7 and 78.8 mm^(-2),***,the size distribution of the inclusions,especially the coarse inclusions with their longest length greater than 8μm,differsmuch from each *** number density of coarse inclusions differs from 0.8 to 1.1 mm^(-2) with processing,and in Al-killed steel,55.5% of the coarse inclusions were titanium nitrides or manganese sulfides,whereas in Zr-killed steel,only 22.5% of the coarse inclusions were titanium nitrides and manganese *** titanium nitrides were especially detrimental to the impact *** number density of them should be below 0.33 mm-2 in order to guarantee the best possible toughness in the steel in *** average crystallographic grain size detected by electron backscattered diffraction of Zr-killed steel(4

关键词： Microalloyed heavy plate Zr-killed technology Inclusion modification Mechanical property

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