检索结果-南通市图书馆

Constraints on holographic QCD phase transitions from PTA observations

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) 2025年第1期Mechanics & Astronomy) .卷 71-78页

作者： Song He Li Li Sai Wang Shao-Jiang Wang Center for Theoretical physics and College of physics Jilin University school of physical science and technology Ningbo University Max Planck Institute for Gravitational physics (Albert Einstein Institute) CAS Key laboratory of Theoretical physics Institute of Theoretical Physics Chinese Academy of Sciences school of Fundamental physics and Mathematical sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) school of physical sciences University of Chinese Academy of Sciences (UCAS) Theoretical physics Division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(GWs) within the standard model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

Buried interface bridging for inverted cesium-formamidinium triiodide perovskite solar cells with long operational stability

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 Chemistry 2025年第01期 163-173页

作者： Chenhui Zhang Chunjun Liang Fulin Sun Ting Zhu Xinghai Huang Yuzhu Guo Xinyu Guo Kunyang Ge Dan Li Fangtian You Zhiqun He Key laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic TechnologyBeijing Jiaotong University Department of physics School of Physical Science and Engineering Beijing Jiaotong University

In the field of perovskite solar cells(PSCs), the research on defects in the buried interface has been relatively limited due to its non-exposure; however, this interface significantly impacts the performance enhancement of inverted PSCs. This study employs phenylethylammonium chloride(PEACl) molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs) and facilitate the uniform nucleation and growth of perovskite films on the substrate. Furthermore, the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination loss. Following these optimizations, the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE) of 24.11%, with significant improvements in storage, thermal stability, and operational stability. Particularly noteworthy is the device's performance in an unencapsulated state, whereas after 1,500 hours of continuous light operation stability testing, it retains 97% of its original efficiency. This study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.

关键词：

同方期刊数据库

Observation of topological charge transformations in acoustic vortex using passive periodic systems

在线全文

学校读者我要写书评

暂无评论

science China(physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 140-147页

作者： Di-Chao Chen Xie Liu Changqing Xu Da-Jian Wu Ying Cheng Xiao-Jun Liu school of physics and technology Nanjing Normal University Key laboratory of Modern Acoustics School of Physics Nanjing University

Vortex transmutation utilizes a periodic system, which not only enables the alteration of the topological charge(TC) of unstable input vortices but also facilitates their transformation into stable structures. This approach is crucial for investigating the characteristics of vortices in various wave systems. Here, we achieve acoustic vortex TC transmutation by employing a welldesigned dual-structured plate external system(DPES). The interactions between the acoustic vortex and the finite-order discrete rotational symmetry lead to the transformation of its topological charge when complete rotational symmetry is broken to Nthorder discrete symmetry. Our results experimentally demonstrate the acoustic vortex TC transmutation based on passive artificial structures, enabling numerous applications in particle manipulation and information multiplexing as well as advancing our understanding and control over free-space acoustic vortices.

关键词： acoustic vortex topological charge transformation artificial structure

Alternating twisted multilayer graphene:generic partition rules,double flat bands,and orbital magnetoelectric effect

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 1037-1044页

作者： Bo Xie Ran Peng Shihao Zhang Jianpeng Liu school of physical science and technology ShanghaiTech UniversityShanghai201210China shanghaitech laboratory for topological physics ShanghaiTech UniversityShanghai201210China

Recently the alternating twisted trilayer graphene is discovered to exhibit unconventional superconductivity,which motivates us to study the electronic structures and possible correlation effects for this class of alternating twisted multilayer graphene(ATMG)*** this work we consider generic ATMG systems with M-L-N stacking configurations,in which the M(L)graphene layers and the L(N)layers are twisted by an angleθ(−θ).Based on analysis from a simplified k⋅p model approach,we derive generic partition rules for the low-energy electronic structures,which exhibit various band dispersions including two pairs of flat bands and flat bands co-existing with various gapless Fermionic *** a mirror-symmetric ATMG system with doubled flat bands,we further find that Coulomb interactions may drive the system into a state with intertwined electric polarization and orbital magnetization orders,which can exhibit an interaction-driven orbital magnetoelectric effect.

关键词： twisted bands orbital

Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

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

Journal of Energy Chemistry 2025年第1期100卷 286-308页

作者： Yuhao Peng Yuefeng Song Ihar Razanau Juanxiu Xiao Wei Xiao Di Hu Guoxiong Wang College of Chemistry and Molecular sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key laboratory of Catalysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences laboratory of physical-Chemical Technologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of Chemical and Environmental Engineering University of Nottingham Ningbo China

Methane, an abundant one-carbon（C1） resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO2emissions and coke deposition. Electrochemical conversion of methane（ECM） using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO2emission.

关键词： Methane Electrochemical conversion Reaction mechanism Catalyst design Electrode Electrocatalysis

Visualization of ferromagnetic domains in vanadium-doped topological insulator thin films and heterostructures

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tungsten 2023年第3期5卷 288-299页

作者： Ying-Jie Ma Ti-Rui Xia Wen-Bo Wang school of physical science and technology ShanghaiTech UniversityShanghai 201210China shanghaitech laboratory for topological physics ShanghaiTech UniversityShanghai 201210China

Magnetically doped topological insulator(TI) thin films and related heterostructures have been extensively studied for years due to their exotic quantum transport properties and potential applications in low-dissipation electronic devices and quantum *** selection of magnetic dopants is crucial to realize a high-quality magnetic TI with a robust ferromagnetic ordering and a preserved topological band *** this paper,we briefly review the recent magnetic domain imaging works in vanadium-doped magnetic topological insulator thin films and *** cryogenic magnetic force microscopy and in situ transport measurements,a ferromagnetic domain behavior has been demonstrated in V-doped Sb2Te3(ST) and Cr,V co-doped(Bi,Sb)2Te3(BST) thin *** direct visualization of long-range ferromagnetic ordering in a quantum anomalous Hall(QAH) system sheds light on enhancing the QAH temperature by improving the *** advantage of the different coercivity of Cr-and V-doped BST films,an axion insulating state has been observed in Cr-doped BST/BST/V-doped BST sandwich *** antiparallel magnetization alignment,which is the key ingredient for realization of axion insulating state,has been directly visualized via magnetic imaging at various magnetic *** V-doped ST/ST heterostructures also provide a platform for Berry phase engineering in momentum *** suppressing the anomalous Hall effect in such heterostructures,an intrinsic topological Hall effect can be revealed,which resolved the long-term puzzle of the origin of THE in the ultrathin ferromagnetic thin films and two-dimensional *** review of magnetic domain imaging in vanadium-doped topological insulators and heterostructures inspires further exploration of quantum transport properties in magnetic topological insulators and deepens the understanding of the interplay between the magnetic ordering and topological electronic band structures in magne

关键词： Vanadium-doped topological insulator Magnetic force microscopy Ferromagnetic domain Quantum anomalous Hall effect topological Hall effect

维普期刊数据库

Magnetic domain structures in ultrathin Bi_(2)Te_(3)/CrTe_(2) heterostructures

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第8期33卷 511-517页

作者：夏体瑞杨笑天张逸凡刘馨琪蔡新雨刘畅姚岐寇煦丰王文波 school of physical science and technology ShanghaiTech UniversityShanghai 201210China school of Information science and technology ShanghaiTech UniversityShanghai 201210China shanghaitech laboratory for topological physics ShanghaiTech UniversityShanghai 201210China Department of Materials science Fudan UniversityShanghai 200438China

Chromium tellurium compounds are important two-dimensional van der Waals ferromagnetic materials with high Curie temperature and chemical stability in air,which is promising for applications in spintronic ***,highquality spin-orbital-torque(SOT)device,Bi_(2)Te_(3)/CrTe_(2)heterostructure was epitaxially grown on Al_(2)O_(3)(0001)*** Hall measurements indicate the existence of strong ferromagnetism in this device with the CrTe_(2)thickness down to 10 *** order to investigate its micromagnetic structure,cryogenic magnetic force microscope(MFM)was utilized to measure the magnetic domain evolutions at various temperatures and magnetic *** virgin domain state of the device shows a worm-like magnetic domain structure with the size around 0.6μm-0.8μ*** irregular-shape magnetic domains(>1μm)can be induced and pinned,after the field is increased to coercive field and ramped back to low *** temperature-dependent MFM signals exhibit a nice mean-field-like ferromagnetic transition with Curie temperature around 201.5 K,indicating a robust ferromagnetic *** a device can be potentially implemented in future magnetic memory technology.

关键词： CrTe_(2) magnetic domain magnetic force microscopy

维普期刊数据库

Model Hamiltonian for the Quantum Anomalous Hall State in Iron-Halogenide

在线全文

学校读者我要写书评

暂无评论

Chinese physics Letters 2020年第9期37卷 67-72页

作者： Qian Sui Jiaxin Zhang Suhua Jin Yunyouyou Xia Gang Li school of physical science and technology ShanghaiTech UniversityShanghai 200031China Institute for Advanced Study Tsinghua UniversityBeijing 100084China shanghaitech laboratory for topological physics ShanghaiTech UniversityShanghai 200031China

We examine quantum anomalous Hall(QAH)insulators with intrinsic magnetism displaying quantized Hall conductance at zero magnetic *** spin-momentum locking of the topological edge stats promises QAH insulators with great potential in device applications in the field of ***,we generalize Haldane’s model on the honeycomb lattice to a more realistic two-orbital case without the artificial real-space complex ***,we introduce an intraorbital coupling,stemming directly from the local spin-orbit coupling(SOC).Our dxy/dx2-y2 model may be viewed as a generalization of the bismuthene px/py-model for correlated *** promises a large SOC gap,featuring a high operating *** two-orbital model nicely explains the low-energy excitation and the topology of two-dimensional ferromagnetic ***,we find that electronic correlations can drive the QAH states to a c=0 phase,in which every band carries a nonzero Chern *** work not only provides a realistic QAH model,but also generalizes the nontrivial band topology to correlated orbitals,which demonstrates an exciting topological phase transition driven by Coulomb *** the model and the material candidates provide excellent platforms for future study of the interplay between electronic correlations and nontrivial band topology.

关键词： temperature. orbital nontrivial

维普期刊数据库

Effects of pressure and doping on Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2024年第18期185卷 147-154页

作者： Mingxin Zhang Cuiying Pei Qi Wang Yi Zhao Changhua Li Weizheng Cao Shihao Zhu Juefei Wu Yanpeng Qi school of physical science and technology ShanghaiTech UniversityShanghai 201210China shanghaitech laboratory for topological physics ShanghaiTech UniversityShanghai 201210China Shanghai Key laboratory of High-resolution Electron Microscopy ShanghaiTech UniversityShanghai 201210China

Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable *** to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen *** remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper ***,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper *** results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper *** find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 *** study sheds light on the exploration of high-Tc superconductivity in nickelates.

关键词： Unconventional superconductivity High pressure Nickelates Ruddlesden-Popper phases