检索结果-南通市图书馆

Chinese Physics Letters 1998年第9期15卷 680-682页

作者： CHEN Xiao-jia GONG Chang-de department of Physics National Laboratory of Solid State MicrostructuresInstitute for Solid State PhysicsNanjing UniversityNanjing 210093 Center for Advanced Studies in science and Technology of microstructures Nanjing 210093

The pressureinduced changes of hole concentration and pressure effects on Tc in HgBa2CuO4+δ(δ=0.07-0.39)have been investigated on the basis of the pressureinduced charge transfer *** calculations show that large enhancements in Tc under high pressure can be obtained for materials which are underdoped,and not for compounds which have nearly optimal hole *** the other hand,Tc enhancements in compounds which are heavily overdoped are found to be quite *** theoretical prediction is in agreement with *** possible intrinsic factors which are responsible for the pressure dependence of the maximum Tc are discussed within the van Hove singularity scenario.

关键词： Transition singularity optimal

Thin film processing and multiferroic properties of Fe-BaTiO_3 hybrid composite

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 92-95页

作者： Pan YANG Jin-song ZHU Jai-Yeoul LEE Hee Young LEE School of materials science and engineering Yeungnam University Gyeongsan 712-749 Korea national laboratory of solid state microstructures Department of Physics Nanjing University Nanjing 210093 China

Multiferroic bi-layer Fe/BaTiO3 （BTO） thin films were successfully deposited on Pt（200）/MgO（100） substrates using ion beam sputter deposition （1BSD）, and the mutiferroic properties were studied at room temperature. X-ray diffraction （XRD） analyses showed that BTO films were c-axis oriented and epitaxially grown on platinum coated MgO substrates, and （110） epitaxial Fe films were subsequently grown on （001） BTO films. Fe/BTO bi-layer films showed good ferroelectric and ferromagnetic properties at room temperature and the multiferroic coupling was observed, which should be attributed to the hybridization of Fe and Ti occurring at the ferromagnetic-ferroelectric interface.

关键词： multiferroic effect ferroelectricity magnetic properties magnetoelectric effect

Breaking the barriers: advances in acoustic functional materials

在线全文

学校读者我要写书评

暂无评论

national science Review 2018年第2期5卷 159-182页

作者： Hao Ge Min Yang Chu Ma Ming-Hui Lu Yan-Feng Chen Nicholas Fang Ping Sheng national laboratory of solid state microstructures and department of materials science and engineering College of Engineering and Applied SciencesNanjing University department of Physics Hong Kong University of Science and Technology department of Mechanical engineering Massachusetts Institute of Technology Collaborative Innovation Center of Advanced microstructures Nanjing University

Acoustics is a classical field of study that has witnessed tremendous developments over the past 25 *** by the novel acoustic effects underpinned by phononic crystals with periodic modulation of elastic building blocks in wavelength scale and acoustic metamaterials with localized resonant units in subwavelength scale, researchers in diverse disciplines of physics, mathematics, and engineering have pushed the boundary of possibilities beyond those long held as unbreakable limits. More recently, structure designs guided by the physics of graphene and topological electronic states of matter have further broadened the whole field of acoustic metamaterials by phenomena that reproduce the quantum effects classically. Use of active energy-gain components, directed by the parity–time reversal symmetry principle,has led to some previously unexpected wave characteristics. It is the intention of this review to trace historically these exciting developments, substantiated by brief accounts of the salient milestones. The latter can include, but are not limited to, zero/negative refraction, subwavelength imaging, sound cloaking, total sound absorption, metasurface and phase engineering, Dirac physics and topology-inspired acoustic engineering, non-Hermitian parity–time synthetic active metamaterials, and one-way propagation of sound waves. These developments may underpin the next generation of acoustic materials and devices, and offer new methods for sound manipulation, leading to exciting applications in noise reduction, imaging, sensing and navigation, as well as communications.

关键词： acoustic metamaterials phononic crystals topological acoustics PT-symmetry synthetic acoustics sound absorption

Growth and Properties of Blue and Amber Complex Light Emitting InGaN/GaN Multi-Quantum Wells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第8期28卷 247-249页

作者： XIE Zi-Li ZHANG Rong LIU Bin XIU Xiang-Qian SU Hui LI Yi HUA Xue-Mei ZHAO Hong CHEN Peng HAN Ping SHI Yi ZHENG You-Dou Jiangsu Provincial Key laboratory of Advanced Photonic and Electronic materials and National Laboratory of Solid State MicrostructuresSchool of Electronics Science and EngineeringNanjing UniversityNanjing 210093

Blue-red complex light emitting InGaN/GaN multi-quantum well(MQW)structures are fabricated by metal organic chemical vapor deposition(MOCVD).The structures are grown on a 2-inch diameter(0001)oriented(c−face)sapphire substrate,which consists of an approximately 2-µm−thick GaN template and a five-period layer consisting of a 4.9-nm-thick In0.18Ga0.82N well layer and a GaN barrier *** surface morphology of the MQW structures is observed by an atomic force microscope(AFM),which indicates the presence of islands of several tens of nanometers in height on the *** high resolution x−ray diffraction(XRD)θ/2θscan is carried out on the symmetric(0002)of the InGaN/GaN MQW *** least four order satellite peaks presented in the XRD spectrum indicate that the thickness and alloy compositions of the individual quantum wells are repeatable throughout the active *** the 364 nm GaN band edge emission,two main emissions of blue and amber light from these MQWs are found,which possibly originate from the carrier recombinations in the InGaN/GaN QWs and InGaN quasi-quantum dots embedded in the QWs.

关键词： InGaN/GaN sapphire quantum

ZnO nanorod arrays with tunable size and field emission properties on an ITO substrate achieved by an electrodeposition method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第6期21卷 525-530页

作者：巩江峰窦召明王志强张博朱卫华张开骁刘明熠朱浩周剑锋 department of Physics Hohai University national laboratory of solid state microstructures Nanjing University College of engineering and Applied sciences Nanjing University

In the present work, vertically aligned ZnO nanorod arrays with tunable size are successfully synthesized on nonseeded ITO glass substrates by a simple electrodeposition method. The effect of growth conditions on the phase, morphology, and orientation of the products are studied in detail by X-ray diffraction （XRD）, scanning electron mi-croscopy （SEM）, and transmission electron microscopy （TEM）. It is observed that the as-prepared nanostructures exhibit a preferred orientation along c axis, and the size and density of the ZnO nanorod can be controlled by changing the concentration of ZnC12. Field emission properties of the as-synthesized samples with different diameters are also studied, and the results show that the nanorod arrays with a smaller diameter and appropriate rod density exhibit better emission properties. The ZnO nanorod arrays show a potential application in field emitters.

关键词： ZnO nanorod microstructure electrodeposition field emission properties

Discovery of a new nontoxic cuprate superconducting system Ga-Ba-Ca-Cu-O

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2018年第9期61卷 82-85页

作者： Yue Zhang Wenhao Liu Jin Si Xiyu Zhu Chengping He Haonan Zhao Hai-Hu Wen Center for Superconducting Physics and materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced Microstructures Nanjing University

Superconductivity is observed in a new nontoxic cuprate system Ga-Ba-Ca-Cu-O,with T_c=82 K for Ga Ba_2Ca_5Cu_6O_(14+δ)(Ga-1256)and T_c=116 K probably for Ga Ba_2Ca_3Cu_4O_(10+δ)(Ga-1234)or Ga Ba_2Ca_2Cu_3O_(8+δ)(Ga-1223),*** compounds are fabricated by solid state reaction method under high pressure and high *** are characterized by resistivity,magnetization and X-ray diffraction(XRD)*** temperature dependence of magnetization measured in both zero-field-cooled and field-cooled processes on one sample(S1)shows two superconducting transitions at about 82 K and113 *** estimated shielding fraction for the phase with T_cof 82 K is about 67%,while the fraction for another phase with T_(c )of 113 K is quite *** XRD Rietveld refinement for S1 indicates two main phases existing in the sample,Ga-1256 with fraction of about 58%and non-superconducting Ca_(0.85)Cu O_2with fraction of about 42%***,we can conclude the superconducting phase with transition temperature of 82 K is due to *** resistivity measurement also confirms the superconductivity for S1,and the resistivity reaches zero at about 82 *** temperature dependence of magnetization for another sample(S2)shows much higher superconducting shielding fraction for the phase with T_cof 116 K,which may be a promising prospective for the synthesis of Ga-1234 or Ga-1223 phase.

关键词： cuprates high pressure and high temperature superconductivity

Superconductivity at 44.4 K achieved by intercalating EMIM^(+) into FeSe

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第10期30卷 548-553页

作者： Jinhua Wang Qing Li Wei Xie Guanyu Chen Xiyu Zhu Hai-Hu Wen Center for Superconducting Physics and materials National Laboratory of Solid State Microstructures and Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Superconductivity with transition temperature Tc above 40 K was observed in protonated FeSe(Hy-FeSe)previously with the ionic liquid EMIM-BF4 used in the electrochemical ***,the real superconducting phase is not clear until *** detailed structural,magnetization,and electrical transport measurements are *** using similar protonating technique on FeSe single crystals,we obtain superconducting samples with Tc above 40 *** show that the obtained superconducting phase is not Hy-FeSe but actually an organic-ion(C6H11N+2 referred to as EMIM^(+))-intercalated phase(EMIM)*** using x-ray diffraction technique,two sets of index peaks corresponding to different c-axis lattice constants are detected in the obtained samples,which belong to the newly formed phase of intercalated(EMIM)xFeSe and the residual FeSe,*** superconductivity of(EMIM)xFeSe with Tc of 44.4 K is confirmed by resistivity and magnetic susceptibility *** dependence of resistivity with different applied magnetic fields reveals that the upper critical field Hc2 is quite high,while the irreversibility field Hirr is suppressed quickly with increasing temperature till about 20 *** indicates that the resultant compound has a high anisotropy with a large spacing between the FeSe layers.

关键词： FeSe iron-based superconductor electrochemical intercalation

Contrasting physical properties of the trilayer nickelates Nd4Ni3O10 and Nd4Ni3O8

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2021年第2期64卷 98-104页

作者： Qing Li ChengPing He XiYu Zhu Jin Si XinWei Fan Hai-Hu Wen Center for Superconducting Physics and materials National Laboratory of Solid State Microstructures and Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China

We report the crystal structures and physical properties of trilayer nickelates Nd4Ni3O10and *** of magnetization and electrical resistivity display contrasting behaviors in the two ***4Ni3O10shows a paramagnetic metallic behavior with a metal-to-metal phase transition(T^*)at about 162 K,as revealed by both magnetic susceptibility and *** magnetoresistance and Hall coefficient results show a negative magnetoresistance at low temperatures and the carrier type of Nd4Ni3O10is dominated by hole-type charge *** significant enhancement of Hall coefficient and resistivity below T*suggests that effective charge carrier density decreases when cooling through the transition *** contrast,Nd4Ni3O8 shows an insulating *** addition,this compound shows a paramagnetic behavior with the similar magnetic moment as that of Nd4Ni3O10derived from the Curie-Weiss *** may suggest that the magnetic moments in both systems are contributed by Nd^3+ *** applying pressures up to about 49 GPa,the insulating behavior is still present and becomes even stronger under a high *** results suggest that the different Ni configurations(Ni^1+/2+ or Ni^2+/3+)and the changes of coordination environment of Ni sites may account for the contrasting behaviors in trilayer nickelates Nd4Ni3O10and Nd4Ni3O8.

关键词： trilayer nickelate Nd4Ni3O10 and Nd4Ni3O8 high-pressure study

Bipolarized intrinsic faradaic layer on a semiconductor surface under illumination

在线全文

学校读者我要写书评

暂无评论

national science Review 2023年第4期10卷 114-122页

作者： Mengfan Xue Zhiqiang Chu Dongjian Jiang Hongzheng Dong Pin Wang Gengzhi Sun Yingfang Yao Wenjun Luo Zhigang Zou Eco-materials and Renewable Energy Research Center (ERERC) Jiangsu Key Laboratory for Nano Technology National Laboratory of Solid State Microstructures and Department of Physics Nanjing University national laboratory of solid state microstructures College of Engineering and Applied Sciences Nanjing University Key laboratory of Flexible Electronics (KLOFE) and Institute of Advanced materials (IAM) Nanjing Tech University

Interface charge transfer plays a key role in the performance of semiconductors for different kinds of solar energy utilization, such as photocatalysis, photoelectrocatalysis, photochromism and photo-induced superhydrophilicity. In previous studies, different mechanisms have been used to understand interface charge transfer processes. However, the charge transfer mechanism at the solid/liquid interface remains a controversial topic. Here, taking TiO2as a model, we find and prove, via experiments, the new characteristic of photo-induced bipolarity of the surface layer(reduction faradaic layer and oxidation faradaic layer) on a semiconductor for the first time. Different from energy level positions in the classic surface states transfer mechanism, the potential window of a surface faradaic layer is located out of the forbidden band. Moreover,we find that the reduction faradaic layer and oxidation faradaic layer serve as electron and hole transfer mediators in photocatalysis, while the bipolarity or mono-polarity of the surface layer on a semiconductor depends on the applied potential in photoelectrocatalysis. The new characteristic of bipolarity can also offer new insights into the charge transfer process at the semiconductor/liquid interface for solar energy utilization.

关键词： semiconductor surface interface charge transfer reduction faradaic layer oxidation faradaic layer faradaic layer descriptor

Superconductivity in Li OHFe S single crystals with a shrunk c-axis lattice constant

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2017年第2期Mechanics & Astronomy) .卷 50-54页

作者： Hai Lin Rui Zhe Kang Lu Kong XiYu Zhu Hai-Hu Wen Center for Superconducting Physics and materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced Microstructures Nanjing University

By using a hydrothermal ion-exchange method, we have successfully grown superconducting crystals of Li OHFe S with Tcof about 2.8 K. Being different from the sister sample(Li1-xFex)OHFe Se, the energy dispersion spectrum analysis on Li OHFe S shows that the Fe/S ratio is very close to 1:1, suggesting an almost charge neutrality and less electron doping in the Fe S planes of the system. Comparing with the non superconducting Li OHFe S crystal, each peak of the X-ray diffraction pattern of the superconducting crystal splits into two, and the diffraction peaks locating at lower reflection angles are consistent with that of non-superconducting ones. The rest set of diffraction peaks with higher reflection angles is corresponding to the superconducting phase, suggesting that the superconducting phase may has a shrunk c-axis lattice constant. Magnetization measurements indicate that the magnetic shielding due to superconductivity can be quite high under a weak magnetic field. The resistivity measurements under various magnetic fields show that the upper critical field is quite low, which is similar to the tetragonal Fe S superconductor.

关键词： iron chalcogenides magnetic properties transport properties