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Relative Stability of FeS2 Polymorphs: Ab Initio Study Using random phase approximation

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Relative Stability of FeS2 Polymorphs: Ab Initio Study Using...

Magnetic Behaviour of Antiferromagnetic Monolayer under an External Field

第十三届全国量子化学会议

作者： Min-Ye Zhang Hong Jiang College of Chemistry and Molecular Engineering Peking University

Iron pyri te(FeS) has attracted a lot of interest recently because of its potential applications in photovoltaic and photoelectrochemical devices, due to i ts sui table band gap(about 0.95 eV), remarkable optical absorption, nontoxici ty and easy accessibility.[1] Regarding theoretical studies, densi ty functional theor y(DFT) in local or semi-local densi ty approximations have confronted difficul ties in tackling FeS, one of which is the inability of common density functional approximations to correctly account for the thermodynamic relative stability between two FeS polymorphs, pyri te(P) and marcasite(M).[2,3] In this work, the relative stability of P and M is inves tigated by using the adiabatic-connection fluctuation-dissipation theory(ACFDT) wi th random phase approximation(RPA). It is shown that P is more stable than M by about 20 meV per formula uni t in terms of the enthalpy of formation calculated from RPA, agreeing better with experiment than those from(semi-)local and hybrid functional HSE06. Such concl usions can be drawn consistently, even when Kohn-Sham orbitals from di fferent functional approximations are used as input for RPA. We also consider the zero-poi nt energy corrections and fini te temperature effects, which are found to be insigni ficant compared to that from the incl usion of high order dynamical correlation i n the ACFDT-RPA approach. The res ul ts for FeS in this work are consis tent wi th our previous findings in TiO2,[ 4]indicating the importance of considering high-order dynamical correlation as described by ACFDT-RPA for a correct description of the relative stability of competing phases that are energetically very close.

关键词： Iron pyri te Thermodynamic stability Density functional theory random phase approximation

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Chinese Physics Letters 2003年第9期20卷 1593-1595页

作者：黄晨王怀玉王恩哥 DepartmentofPhysics TsinghuaUniversityBeijing100084 InstituteofPhysics ChineseAcademyofSciencePOBox603Beijing100080

Magnetic behaviour of antiferromagnetic monolayer under external field is studied. This is the first time to calculate all components of spin statistical average of an antiferromagnetic system with the random-phase approximation. To do so, a method is developed by many-body Green's function theory. Magnetization and susceptibility are investigated when external field is applied in either the x- or z-direction. The results are compared with the ferromagnetic monolayer.

关键词： Monolayers Antiferromagnetism external electric field Magnetic force Green's function random phase approximation

Ferromagnetism in one-dimensional Hubbard model induced by the next-nearest-neighbor hopping at electron density 3/2

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Chinese Physics B 2014年第11期23卷 450-453页

作者：杨媛媛张健潘晖王海龙 State Key Laboratory of Software Development Environment and Department of Physics Beijing University of Aeronautics and Astronautics

Ferromagnetism in the one-dimensional Hubbard model with the next-nearest-neighbor hopping is explored by using the exact-diagonalization method in a small cluster and the equation-of-motion method in the thermodynamic limit with electron density n = 3/2. With these two complementary methods, it is found that an intermediate value of the next-nearest- neighbor hopping amplitude tl tends to stabilize the fully polarized ferromagnetic state under the condition that the on-site coulomb interaction U is sufficiently large in our model. The ground-state phase diagram of the model is presented in the tl-U plane.

关键词： ferromagnetism frustration effect random phase approximation

Superallowed Fermi transitions in RPA with a relativistic point-coupling energy functional

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Science China(Physics,Mechanics & Astronomy) 2011年第6期54卷 1131-1136页

作者： LI ZhaoXi YAO JiangMing CHEN Hong School of Physical Science and Technology Southwest UniversityChongqing 400715China

The self-consistent random phase approximation (RPA) approach with the residual interaction derived from a relativistic pointcoupling energy functional is applied to evaluate the isospin symmetry-breaking corrections δ c for the 0+ → 0+ superallowed Fermi *** these δ c values,together with the available experimental f t values and the improved radiative corrections,the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is *** with the consideration of uncertainty,the sum of squared top-row elements has been shown to deviate from the unitarity condition by 0.1% for all the employed relativistic energy functionals.

关键词： superallowed Fermi transition random phase approximation relativistic point-coupling energy functional CabibboKobayashi-Maskawa matrix

Neutron star core-crust transition and the crustal moment of inertia in the nonlinear relativistic Hartree approximation

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Chinese Physics C 2024年第3期48卷 133-141页

作者：李牛韦斯纳杨荣瑶叶婧蒋维洲 School of Physics Southeast UniversityNanjing 211189China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

We investigate the effects of theσmeson mass(m_(σ)),symmetry energy,and slope of the symmetry energy on the neutron star core-crust transition density and the crustal moment of inertia(ΔI/I)in the nonlinear relativistic Hartree approach(RHA),which includes vacuum *** the core-crust transition density(ρ_(t)),pressure(P_(t)),and neutron star radius(R),which are all dependent on the symmetry energy,contribute to determiningΔI/I,we find that changing only the slope of symmetry energy within a reasonable range is not sufficient to reachΔI/I≥7%to achieve the large glitches of the Vela ***,since all three factors(ρ_(t),P_(t),and R)increase with the increase in mσthrough scalar vacuum polarization,adjusting mσcan easily achieveΔI/I≥7%.

关键词： symmetry energy relativistic Hartree approximation random phase approximation core-crust transition density pulsar glitch

Thied—Order approximation of 0^＋＋ Glueball Mass and Wavefunction of （2＋1）—Dimensional SU（3） Lattice Gauge Theory

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Communications in Theoretical Physics 2001年第1期35卷 28-31页

作者： LIJie－Ming CHENQi－Zhou 等 DepartmentofPhysics ZhoungshanUniversityGuangzhou510275China

The random phase approximation is applied to the coupled-cluster expansions of lattice gauge theory (LGT). Using this method, wavefunctions are approximated by linear combination of graphs consisting of only one connected Wilson loop. We study the excited state energy and wavefunction in (2+1)-D SU(3) LGT up to the third order. The glueball mass shows a good scaling behavior.

关键词： random phase approximation coupled-cluster expansion Wilson loop glueball mass

p+ip-wave pairing symmetry at type-II van Hove singularities

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Frontiers of physics 2021年第5期16卷 191-197页

作者： Yin-Xiang Li Xiao-Tong Yang Tin Ka-Ping College of Science University of Shanghai for Science and TechnologyShanghai200093China

Based on the random phase approximation calculation in two-orbital honeycomb lattice model,we investigate the pairing symmetry of Ni-based transition-metal trichalcogenides by electron doping access to type-II van Hove singularities(vHs).We find that chiral even-parity d+id-wave(Eg)state is suppressed by odd-parity p+ip-wave(Eu)state when electron doping approaches the type-II *** type-II vHs peak in density of states(DOS)enables to strengthen the ferromagnetic fluctuation,which is responsible for triplet *** competition between antiferromagnetic and ferromagnetic fluctuation results in pairing phase transition from singlet to triplet *** Ni-based transition-metal trichalcogenides provide a promising platform to unconventional superconductor emerging from electronic DOS.

关键词： type-II van Hove singularities pairing symmetry random phase approximation unconventional superconductor