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spin and spin-orbit coupling effects in nickel-based superalloys:A first-principles study on Ni_(3)Al doped with Ta/W/Re

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Chinese Physics B 2022年第1期31卷 458-464页

作者：刘立平曹晋郭伟王崇愚 Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE) School of PhysicsBeijing Institute of TechnologyBeijing 100081China Department of Physics Tsinghua UniversityBeijing 100084China

Heavy elements(X=Ta/W/Re)play an important role in the performance of superalloys,which enhance the strength,anti-oxidation,creep resistance,and anti-corrosiveness of alloy materials in a high-temperature *** the present research,the heavy element doping effects in FCC-Ni(γ)and Ni_(3)Al(γ')systems are investigated in terms of their thermodynamic and mechanical properties,as well as electronic *** lattice constant,bulk modulus,elastic constant,and dopant formation energy in non-spin,spin polarized,and spin-orbit coupling(SOC)calculations are *** results show that the SOC effects are important in accurate electronic structure calculations for alloys with heavy *** find that including spin for bothγandγ'phases is necessary and sufficient for most cases,but the dopant formation energy is sensitive to different spin effects,for instance,in the absence of SOC,even spin-polarized calculations give 1%to 9%variance in the dopant formation energy in our *** structures calculations indicate that spin polarization causes a split in the metal d states,and SOC introduces a variance in the spin-up and spin-down states of the d states of heavy metals and reduces the magnetic moment of the system.

关键词： nickel-based superalloys Ni_(3)Al spin spin-orbit coupling mechanical properties electronic structures

Itinerant ferromagnetism entrenched by the anisotropy of spin-orbit coupling in a dipolar Fermi gas

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Frontiers of physics 2023年第5期18卷 227-235页

作者： Xue-Jing Feng Jin-Xin Li Lu Qin Ying-Ying Zhang ShiQiang Xia Lu Zhou ChunJie Yang ZunLue Zhu Wu-Ming Liu Xing-Dong Zhao School of Physics Henan Normal UniversityXinxiang 453000China Department of Physics School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

We investigate the itinerant ferromagnetism in a dipolar Fermi atomic system with the anisotropic spin–orbit coupling(SOC),which is traditionally explored with isotropic contact *** first study the ferromagnetism transition boundaries and the properties of the ground states through the density and spin-flip distribution in momentum space,and we find that both the anisotropy and the magnitude of the SOC play an important role in this *** propose a helpful scheme and a quantum control method which can be applied to conquering the difficulties of previous experimental observation of itinerant *** further study reveals that exotic Fermi surfaces and an abnormal phase region can exist in this system by controlling the anisotropy of SOC,which can provide constructive suggestions for the research and the application of a dipolar Fermi ***,we also calculate the ferromagnetism transition temperature and novel distributions in momentum space at finite temperature beyond the ground states from the perspective of experiment.

关键词： itinerant ferromagnetism spin-orbit coupling cold atom quantum simulation dipolar Fermi gas dipole-dipole interaction

spin-orbit coupling adjusting topological superfluid of mass-imbalanced Fermi gas

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Chinese Physics B 2022年第9期31卷 208-216页

作者：冯鉴张伟伟林良伟蔡启鹏张义财马胜灿刘超飞 School of Science Jiangxi University of Science and TechnologyGanzhou 341000China School of Physics and Electronic Engineering Guangzhou UniversityGuangzhou 510006China

Topological superfluid state is different from the normal superfluid one due to the excitation energy gap on the *** to obtain the topological superfluid state by using spin-orbit coupling to control the s-waves paired mass-imbalanced Fermi gas is a recent novel *** this paper,we study the topological superfluid phase diagram of two-dimensional mass-imbalanced Fermi gas with Rashba spin-orbit coupling at zero *** find that due to the competition among mass imbalance,pairing interaction and spin-orbit coupling,there is a double-well structure in the thermodynamic potential,which affects the properties of the ground state of the *** comprehensively give the phase diagrams of the system on the plane of spin-orbit coupling and chemical potential,and the phase diagrams on the plane of the reduced mass ratio and two-body binding *** study not only points out the stable region of topolog-ical superfluid state of mass-imbalanced Fermi gas,but also provides a detailed theoretical basis for better observation of topological superfluid state in experiments.

关键词： topological superfluid mass-imbalanced spin-orbit coupling Fermi gas

spin-orbit coupling and Intersystem Crossing in 4H-Pyran-4-thione： CASSCF//TD-B3LYP Study

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Chinese Journal of Chemistry 2007年第10期25卷 1461-1466页

作者：吕玲玲刘新文袁琨王永成汪汉卿 College of Life Science and Chemistry Tianshui Normal University Tianshui Gansu 741001 China College of Chemistry and Chemical Engineering Northwest Normal University Lanzhou Gansu 730070 China Institute of Chemical Physics Chinese Academy of Sciences Lanzhou Gansu 730070 China

The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Harniltonian, the strengths of spin-orbit coupling were estimated, which plays an essential role in the spin transitions between different spin states. Calculated results show that phosphorescence and non-radiative decay via intersystem crossing to the So state are concurrent processes occurring at the T1 state. A rapid depletion of the S1 state via intersystem crossing to the T1 state can be mediated by the T2 state, if spin relaxation is fast within the triplet levels. Our calculated results are in close agreement with experimental observations.

关键词： 4H-pyran-4-thione spin-orbit coupling intersystem crossing phosphorescence

spin-orbit coupling in Bose-Einstein condensate and degenerate Fermi gases

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Frontiers of physics 2014年第5期9卷 598-612页

作者： Peng-Jun Wang Jing Zhang State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Taiyuan 030006 China

We review our recent experimental realization and investigation of a spin orbit （SO） coupled Bose Einstein condensate （BEC） and quantum degenerate Fermi gas. By using two counter-propagathlg Ranlan lasers and controlling the different frequency of two R,aman lasers to engineer the atom light interaction, we first study the SO coupling in BEC. Then we study SO coupling in Fermi gas. We, observe the spin dephasing in spin dynamics and momentum distribution asymmetry of the equilibrium state as halhnarks of SO coupling in a Fermi gas. To clearly reveal the, property of SO coupling Fermi gas, we also study the momentmn-resolved radio-frequency spectroscopy which characterizes the energy momentum dispersion and spin composition of the quantum states. We observe the change of errmion surfaces in different helieity branches with different atomic density, which indicates that a Lifshitz transition of the Fermi surface topology change can be found by further cooling the system. At last, we study the momentum-resolved Raman spectroscopy of an ultracoht Fermi gas.

关键词： spin-orbit coupling Bose Einstein condensate Fermi gases topological change momentum-resolved radio-frequency spectroscopy momentum-resolved Raman spectroscopy

Electron resonance-transmission through a driven quantum well with spin-orbit coupling

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Chinese Physics B 2008年第7期17卷 2662-2669页

作者：张存喜王瑞聂一行梁九卿 Department of Physics and Institute of Theoretical Physics Shanxi University Physical Department of Zhejiang Ocean University Department of Physics Yanbei Normal Institute

We have studied the spin-dependent electron transmission through a quantum well driven by both dipole-type and homogeneous oscillating fields. The numerical evaluations show that Dresselhaus spin-orbit coupling induces the splitting of asymmetric Fano-type resonance peaks in the conductivity, in which the dipole modulation and the homogeneous modulation are equivalent. Therefore, we predict that the dipole-type oscillation, which is more practical in the experimental setup, can be used to realize the tunable spin filters by adjusting the field oscillation-frequency and the amplitude as well.

关键词： Fano resonance Floquet channel spin-orbit coupling

Tunable valley filter efficiency by spin-orbit coupling in silicene nanoconstrictions

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Chinese Physics B 2021年第5期30卷 589-594页

作者：施一剑王园春汪鹏君 College of Electrical and Electronic Engineering Wenzhou UniversityWenzhou 325035China

Valley filter is a promising device for producing valley polarized current in graphene-like two-dimensional honeycomb lattice *** relatively large spin-orbit coupling in silicene contributes to remarkable quantum spin Hall effect,which leads to distinctive valley-dependent transport properties compared with intrinsic *** this paper,quantized conductance and valley polarization in silicene nanoconstrictions are theoretically investigated in quantum spin-Hall insulator *** perfect valley filter effect is found by aligning the gate voltage in the central constriction ***,the valley polarization plateaus are shifted with the increase of spin-orbit coupling strength,accompanied by smooth variation of polarization *** findings provide new strategies to control the valley polarization in valleytronic devices.

关键词： valley polarization spin-orbit coupling quantization silicene

Finite size effects on helical edge states in HgTe quantum wells with the spin orbit coupling due to bulk- and structure-inversion asymmetries

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Chinese Physics B 2014年第3期23卷 498-503页

作者：成志周斌 Department of Physics Hubei University

There is a quantum spin Hall state in the inverted HgTe quantum well, characterized by the topologically protected gapless helical edge states lying within the bulk gap. It has been found that for a strip of finite width, the edge states on the two sides can couple together to produce a gap in the spectrum. The phenomenon is called the finite size effect in quantum spin Hall systems. In this paper, we investigate the effects of the spin-orbit coupling due to bulk- and structure-inversion asymmetries on the finite size effect in the HgTe quantum well by means of the numerical diagonalization method. When the bulk-inversion asymmetry is taken into account, it is shown that the energy gap Eg of the edge states due to the finite size effect features an oscillating exponential decay as a function of the strip width of the HgTe quantum well. The origin of this oscillatory pattern on the exponential decay is explained. Furthermore, if the bulk- and structure-inversion asymmetries are considered simultaneously, the structure-inversion asymmetry will induce a shift of the energy gap Eg closing point. Finally, based on the roles of the bulk- and structure-inversion asymmetries on the finite size effects, a way to realize the quantum spin Hall field effect transistor is proposed.

关键词： quantum spin Hall state finite size effect spin-orbit coupling

Manipulating vortices in F=2 Bose-Einstein condensates through magnetic field and spin-orbit coupling

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Chinese Physics B 2022年第4期31卷 151-156页

作者：朱浩印寿根刘伍明 Key Laboratory of Display Materials and Photoelectric Devices(Ministry of Education) Tianjin Key Laboratory for Photoelectric Materials and DevicesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

We investigate the vortex structures excited by Ioffe-Pritchard magnetic field and Dresselhaus-type spin-orbit coupling in F=2 ferromagnetic Bose-Einstein *** the weakly interatomic interacting regime,an external magnetic field can generate a polar-core vortex in which the canonical particle current is *** the combined effect of spin-orbit coupling and magnetic field,the ground state experiences a transition from polar-core vortex to Mermin-Ho vortex,in which the canonical particle current is *** fixed spin-orbit coupling strengths,the evolution of phase winding,magnetization,and degree of phase separation with magnetic field are ***,with further increasing spin-orbit coupling strength,the condensate exhibits symmetrical density domains separated by radial vortex *** work paves the way to explore exotic topological excitations in high-spin systems.

关键词： Bose-Einstein condensates vortex magnetic field spin-orbit coupling