检索结果-南通市图书馆

维普期刊数据库

Magnetism of NaYbS: From finite temperatures to ground state

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年

作者： Weizhen Zhuo Zheng Zhang Mingtai Xie Anmin Zhang Jianting Ji Feng Jin Qingming Zhang School of Physical Science and Technology Lanzhou University Beijing National Laboratory for condensed matter Physics Institute of Physics Chinese Academy of Sciences

Rare-earth chalcogenide compounds ARECh2（A = alkali or monovalent metal, RE = rare earth, Ch = O, S, Se, Te） are a large family of quantum spin liquid（QSL） candidate materials. NaYbS2is a representative member of the family. Several key issues on NaYbS2, particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state, remain to be addressed. In this paper, we conducted an in-depth and comprehensive study on the magnetism of NaYbS2from finite temperatures to the ground state. Firstly, we successfully detected three crystalline electric field（CEF） excitation energy levels using low-temperature Raman scattering technique. Combining them with the CEF theory and magnetization data, we worked out the CEF parameters, CEF energy levels, and CEF wavefunctions. We further determined a characteristic temperature of ～40 K, above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main role. The characteristic temperature has been confirmed by the temperature-dependent electron spin resonance（ESR） linewidth. Low-temperature ESR experiments on the dilute magnetic doped crystal of NaYb0.1Lu0.9S2further helped us to determine the accurate g-factor. Next, we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat data. Finally, the above studies allow us to explore the ground state magnetism of NaYbS2by using the density matrix renormalization group. We combined numerical calculations and experimental results to demonstrate that the ground state of NaYbS2is a Dirac-like QSL.

关键词：

Single crystal growth and transport properties of narrow-bandgap semiconductor RhP_(2)

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 B 2024年第8期33卷 545-549页

作者：吴德胜郑萍雒建林 Beijing National Laboratory for condensed matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Quantum Science Center of Guangdong–Hong Kong–Macao Greater Bay Area(Guangdong) Shenzhen 518045China

We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity ***-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,*** temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier *** find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap *** high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 *** magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.

关键词： single crystal growth narrow band system electrical transport high mobilities

Single crystal growth and transport properties of narrow-bandgap semiconductor RhP2

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 2024年第8期 563-568页

作者：吴德胜郑萍雒建林 Beijing National Laboratory for condensed matter Physics Institute of Physics Chinese Academy of Sciences Quantum Science Center of Guangdong–Hong Kong–Macao Greater Bay Area (Guangdong) Songshan Lake Materials Laboratory

We report the growth of high-quality single crystals of RhP2,and systematically study its structure and physical properties by transport,magnetism,and heat capacity ***-crystal x-ray diffraction reveals that RhP2adopts a monoclinic structure with the cell parameters a=5.7347（10） ?,b=5.7804（11） ?,and c=5.8222（11） ?,space group P21/c（No.14）.The electrical resistivity ρ（T） measurements indicate that RhP2exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,*** temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier *** find that RhP2has a high mobility μe～210 cm2·V-1·s-1with carrier concentrations ne～3.3 ×1018cm3at 300 K with a narrow-bandgap *** high mobility μereaches the maximum of approximately 340 cm2·V-1·s-1with carrier concentrations ne～2× 1018cm-3at 100 *** magnetic phase transitions are observed from the susceptibility χ（T）and specific heat Cp（T） measurements of *** results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.

关键词：

An Explanation of the Temperature-Dependent Upper Critical Field Data of H3S on the Basis of the Thermodynamics of a Superconductor in a Magnetic Field

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of condensed matter Physics 2024年第3期14卷 45-50页

作者： Gulshan Prakash Malik Gurugram India theory group School of Environmental Sciences Jawaharlal Nehru University New Delhi India

Excellent fits to a couple of the data-sets on the temperature (T)-dependent upper critical field (Hc2) of H3S (critical temperature, Tc ≈ 200 K at pressure ≈ 150 GPa) reported by Mozaffari, et al. (2019) were obtained by Talantsev (2019) in an approach based on an ingenious mix of the Ginzberg-Landau (GL), the Werthamer, Helfand and Hohenberg (WHH), and the Gor’kov, etc., theories which have individually been employed for the same purpose for a long time. Up to the lowest temperature (TL) in each of these data-sets, similarly accurate fits have also been obtained by Malik and Varma (2023) in a radically different approach based on the Bethe-Salpeter equation (BSE) supplemented by the Matsubara and the Landau quantization prescriptions. For T TL, however, while the (GL, WHH, etc.)-based approach leads to Hc2(0) ≈ 100 T, the BSE-based approach leads to about twice this value even at 1 K. In this paper, a fit to one of the said data-sets is obtained for the first time via a thermodynamic approach which, up to TL, is as good as those obtained via the earlier approaches. While this is interesting per se, another significant result of this paper is that for T TL it corroborates the result of the BSE-based approach.

关键词： H3S Upper Critical Field (Hc2) Variation of Hc2 with Temperature Clausius-Clapeyron equation in a magnetic field Behavior of Hc2 for Temperatures Close to 0 K

Emergent ultra-high temperature ferromagnetism in La_(2)CoO_(4±x) thin films

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

Nano Research 2024年第8期17卷 7250-7255页

作者： Ziang Meng Han Yan Peixin Qin Zhuo Yin Peiheng Jiang Xiaorong Zhou Xiaoning Wang Hongyu Chen Li Liu Zhiyuan Duan Guojian Zhao Weisheng Zhao Fengxia Hu Qinghua Zhang Zhicheng Zhong Zhiqi Liu School of Materials Science and Engineering Beihang UniversityBeijing 100191China Beijing National Laboratory for condensed matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Fert Beijing Institute School of Integrated Circuit Science and EngineeringBeihang UniversityBeijing 100191China

Searching for novel ferromagnetic oxides with high Curie temperature(TC)has been one of the main goals for oxide *** well-known perovskite cobaltate LaCoO_(3) is a classical ferromagnet in its thin-film form;however,it suffers from a low TC(~85 K).Here we report a new type of ferromagnetic La-Co-O films with an ultrahigh TC of~820 *** are fabricated by pulsed laser deposition from a LaCoO_(3) target at low oxygen partial *** structural analysis indicates that they crystallize in terms of the Ruddlesden–Popper phase of La_(2)CoO_(4±x).In sharp contrast to the antiferromagnetism of bulk La_(2)CoO_(4),the strong ferromagnetism in the La_(2)CoO_(4±x) thin films is firmly demonstrated by magnetometry measurements,X-ray magnetic circular dichroism characterization,and magnetotransport *** importantly,density functional theory calculations indicate that the nonstoichiometric oxygen induces an antiferromagnetic-to-ferromagnetic phase transition,accompanied by the orbital reconstruction of Co 3d ***,our study provides an attractive strategy for designing or synthesizing exotic magnetic oxides with high ordering temperatures.

关键词： ferromagnetic oxides ultra-high Curie temperature La_(2)CoO_(4) spin current transport oxygen engineering

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

二维范德华磁体的拓扑自旋结构的研究进展

Science Bulletin 2024年第11期69卷 1612-1616页

作者：许洪军刘艺舟 Giovanni Finocchio Kang LWang 于国强 Beijing National Laboratory for condensed matter Physics Institute of PhysicsUniversity of Chinese Academy of SciencesChinese Academy of SciencesBeijing 100190China RIKEN Center for Emergent matter Science(CEMS) Wako 351-0198Japan Department of Mathematical and Computer Sciences Physical Sciences and Earth SciencesUniversity of MessinaMessina 98166Italy Department of Electrical Engineering University of CaliforniaLos Angeles CA 90095USA

The importance of topological spin textures(TSTs), such as skyrmions, merons, hopfions, etc., is due to their static and dynamic properties [1]. They carry a topological number that characterizes the homotopy group Π_(n)(S^(2))(n ∈ Z) and classifies maps from S^(n) to S^(2)(e.g., the skyrmion winding number corresponds to Π_(2)(S^(2))).

关键词：自旋结构 topological homotopy

维普期刊数据库

在线全文

学校读者我要写书评

暂无评论

四电子配对超导体：波函数方法（英文）

Science Bulletin 2024年第15期 2328-2331页

作者：李鹏飞蒋坤胡江平 Beijing National Laboratory for condensed matter Physics and Institute of Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Kavli Institute of Theoretical Sciences University of Chinese Academy of Sciences New Cornerstone Science Laboratory

The BCS theory of superconductivity is one of milestones in condensed matter physics, which successfully unveils the nature of this macroscopic quantum phenomenon at a microscopic level[1,2]. The essential ingredients for any superconductors (SCs) are the two-electron Cooper pairs and their phase coherence [2],where electrons bind together two by two and condense to form a coherent quantum state, as illustrated in Fig. 1a.

关键词：

具有高阶范霍夫奇点的自选轨道耦合体系中的鲁棒拓扑超导（英文）

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 Bulletin 2024年第3期 319-324页

作者：韩欣龙占俊张富春胡江平吴贤新 Kavli Institute for Theoretical Sciences University of Chinese Academy of Sciences Beijing National Laboratory for condensed matter Physics and Institute of Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences

Van Hove singularities in proximity to the Fermi level promote electronic interactions and generate diverse competing instabilities. It is also known that a nontrivial Berry phase derived from spin–orbit coupling can introduce an intriguing decoration into the interactions and thus alter correlated phenomena. However, it is unclear how and what type of new physics can emerge in a system featured by the interplay between van Hove singularities(VHSs) and the Berry phase. Here, based on a general Rashba model on the square lattice, we comprehensively explore such an interplay and its significant influence on the competing electronic instabilities by performing a parquet renormalization group analysis. Despite the existence of a variety of comparable fluctuations in the particle–particle and particle-hole channels associated with higher-order VHSs, we find that the chiral p ± ip pairings emerge as two stable fixed trajectories within the generic interaction parameter space, namely the system becomes a robust topological superconductor. The chiral pairings stem from the hopping interaction induced by the nontrivial Berry phase. The possible experimental realization and implications are discussed. Our work sheds new light on the correlated states in quantum materials with strong spin–orbit coupling(SOC) and offers fresh insights into the exploration of topological superconductivity.

关键词：

Structural,electronic,magnetic and optical properties of neodymium chalcogenides using LSDA+U method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2012年第8期33卷 9-14页

作者： A Shankar D P Rai Sandeep R K Thapa condensed matter theory group Department of PhysicsMizoram UniversityAizawlMizoram-796004India

We have studied the electronic, magnetic and optical properties of neodymium chalcogenides by performing LSDA＋ U and full potential linearized augmented plane wave （FP-LAPW） method. The electronic structure calculation shows that the electronic states in Nd-chalcogenides were mainly contributed by Nd-4f electrons near Fermi energy and 3p, 4p and 5p state electrons of X （S, Se and Te）, respectively. We have also studied the absorption of light via the imaginary parts of the dielectric function of Nd-chalcogenides.

关键词： DFT DOS magnetic moment U

维普期刊数据库