In many cases, the relativistic spin-orbit (SO) interaction can be regarded as a small perturbation to the electronic structure of solids and treated using regular perturbation theory. The major obstacle on this route...
In many cases, the relativistic spin-orbit (SO) interaction can be regarded as a small perturbation to the electronic structure of solids and treated using regular perturbation theory. The major obstacle on this route comes from the fact that the SO interaction can also polarize the electron system and produce some additional contributions to the perturbation theory expansion, which arise from the electron-electron interactions in the same order of the SO coupling. In electronic structure calculations, it may even lead to the necessity of abandoning the perturbation theory and returning to the original self-consistent solution of Kohn-Sham-like equations with the effective potential v̂, incorporating simultaneously the effects of the electron-electron interactions and the SO coupling, even though the latter is small. In this work, we present the theory of self-consistent linear response (SCLR), which allows us to get rid of numerical self-consistency and formulate the last step fully analytically in the first order of the SO coupling. This strategy is applied to the unrestricted Hartree-Fock solution of an effective Hubbard-type model, derived from the first-principles electronic structure calculations in the basis of Wannier functions for the magnetically active states. We show that by using v̂, obtained in SCLR, one can successfully reproduce results of ordinary self-consistent calculations for the orbital magnetization and other properties, which emerge in the first order of the SO coupling. Particularly, SCLR appears to be an extremely useful approach for calculations of antisymmetric Dzyaloshinskii-Moriya (DM) interactions based on the magnetic force theorem, where only by using the total perturbation one can make a reliable estimate for the DM parameters. Furthermore, due to the powerful 2n+1 theorem, the SCLR theory allows us to obtain the total energy change up to the third order of the SO coupling, which can be used in calculations of magnetic anisotropy of
We present calculations for the dependence of the two-photon double ionization (DI) of H2 on the relative orientation of the linear laser polarization to the internuclear axis and the length of the pulse. We use the f...
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We present calculations for the dependence of the two-photon double ionization (DI) of H2 on the relative orientation of the linear laser polarization to the internuclear axis and the length of the pulse. We use the fixed-nuclei approximation at the equilibrium distance of 1.4 a0, where a0=0.529×10−10m is the Bohr radius. Central photon energies cover the entire direct DI domain from 26.5 to 34.0 eV. In contrast to the parallel geometry studied earlier [X. Guan, K. Bartschat, B. I. Schneider, and L. Koesterke, Phys. Rev. A 83, 043403 (2011)], the effect of the pulse duration is almost negligible for the case when the two axes are perpendicular to each other. This is a consequence of the symmetry rules for dipole excitation in the two cases. In the parallel geometry, doubly excited states of 1Σu+ symmetry affect the cross section, while in the perpendicular geometry only much longer-lived 1Πu states are present. This accounts for the different convergence patterns observed in the calculated cross sections as a function of the pulse length. When the photon energy approaches the threshold of sequential DI, a sharp increase of the generalized total cross section (GTCS) with increasing pulse duration is also observed in the perpendicular geometry, very similar to the case of the molecular axis being oriented along the laser polarization direction. Our results differ from those of Colgan et al. [J. Colgan, M. S. Pindzola, and F. Robicheaux, J. Phys. B 41, 121002 (2008)] and Morales et al. [F. Morales, F. Martín, D. A. Horner, T. N. Rescigno, and C. W. McCurdy, J. Phys. B 42, 134013 (2009)], but are in excellent agreement with the GTCSs of Simonsen et al. [A. S. Simonsen, S. A. Sørngård, R. Nepstad, and M. Førre, Phys. Rev. A 85, 063404 (2012)] over the entire domain of direct DI.
Networks often possess mesoscale structures, and studying them can yield insights into both structure and function. It is most common to study community structure, but numerous other types of mesoscale structures also...
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Networks often possess mesoscale structures, and studying them can yield insights into both structure and function. It is most common to study community structure, but numerous other types of mesoscale structures also exist. In this paper, we examine core-periphery structures based on both density and transport. In such structures, core network components are well-connected both among themselves and to peripheral components, which are not well-connected to anything. We examine core-periphery structures in a wide range of examples of transportation, social, and financial networks—including road networks in large urban areas, a rabbit warren, a dolphin social network, a European interbank network, and a migration network between counties in the United States. We illustrate that a recently developed transport-based notion of node coreness is very useful for characterizing transportation networks. We also generalize this notion to examine core versus peripheral edges, and we show that the resulting diagnostic is also useful for transportation networks. To examine the properties of transportation networks further, we develop a family of generative models of roadlike networks. We illustrate the effect of the dimensionality of the embedding space on transportation networks, and we demonstrate that the correlations between different measures of coreness can be very different for different types of networks.
Using a semiclassical model,we investigate the effect of the initial longitudinal velocity of the tunnel-ionized electron on low-energy structure(LES)in above-threshold ionization(ATI)*** analysis shows that the effec...
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Using a semiclassical model,we investigate the effect of the initial longitudinal velocity of the tunnel-ionized electron on low-energy structure(LES)in above-threshold ionization(ATI)*** analysis shows that the effect(reduction or enhancement)of the initial longitudinal velocity pz0 on the LES is dependent on the direction of the initial longitudinal *** the initial longitudinal velocity along the direction of the laser electric field at the moment of tunneling(i.e.,pz0>0),the Coulomb interaction between the photoelectron and ion core is enhanced,while for the initial longitudinal velocity in the opposite direction(i.e.,pz0<0),the Coulomb effect is *** work provides solid evidence that the initial electron longitudinal velocity has considerable effect on the photoelectron dynamics in the ATI process.
Modern theory of the orbital magnetization is applied to the series of prototype insulating perovskite transition metal oxides (orthorhombic YTiO3, LaMnO3, and YVO3, as well as monoclinic YVO3), carrying a net ferroma...
Modern theory of the orbital magnetization is applied to the series of prototype insulating perovskite transition metal oxides (orthorhombic YTiO3, LaMnO3, and YVO3, as well as monoclinic YVO3), carrying a net ferromagnetic (FM) moment in the ground state. For these purposes, we use an effective Hubbard-type model, derived from the first-principles electronic structure calculations and describing the behavior of magnetically active states near the Fermi level. The solution of this model in the mean-field Hartree-Fock approximation with the relativistic spin-orbit coupling typically gives us a distribution of the local orbital magnetic moments, which are related to the site-diagonal part of the density matrix D̂ by the “classical” expression μ0=−μBTr{L̂D̂}. These moments are usually well quenched by the crystal field. In this work, we evaluate “itinerant” corrections ΔM to the net FM moment, suggested by the modern theory. We show that these corrections are small and in most cases can be neglected. Nevertheless, the most interesting aspect of our analysis is that, even for these compounds, which are frequently regarded as prototype Mott insulators, the “itinerant” corrections reveal a strong k dependence in the reciprocal space, following the behavior of Chern invariants. Therefore, the small value of ΔM is the result of strong cancellation of relatively large contributions, coming from different parts of the Brillouin zone. We discuss details as well as possible implications of this cancellation, which depends on the crystal structure as well as the type of the magnetic ground state.
Under the development of society, the dissemination of information plays an increasingly significant role. How to achieve the goal of continually reducing the error rate and enhance the quality of communication and co...
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作者：
XiaoLei HaoJing ChenWeiDong LiBingbing WangXiaodong WangWilhelm BeckerInstitute of Applied Physics and Computational Mathematics
P.O.Box 8009 Beijing 100088 China Institute of Theoretical Physics and Department of Physics
Shanxi University Taiyuan 030006 China Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088 China Institute of Theoretical Physics and Department of Physics Shanxi University Taiyuan 030006 China Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070China Max Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy Max-Born-Strasse 2a 12489 Berlin Germany
So far, nonsequential double ionization (NSDI) of atoms can be well understood within a semiclassical or even classical *** quantum effect appears to be required to explain the data *** theoretically study electron co...
So far, nonsequential double ionization (NSDI) of atoms can be well understood within a semiclassical or even classical *** quantum effect appears to be required to explain the data *** theoretically study electron correlation resulting from NSDI of argon in a low-intensity laser field using a quantum-mechanical S-matrix *** show that quantum interference between the contributions of different intermediate excited states of the singly charged argon ion produces a transition from back-to-back to side-by-side emission with increasing laser intensity, which is in close agreement with the experimental *** higher intensities, this transition is enhanced by the consequences of depletion of the excited states.
作者：
XiaoLei HaoJing ChenWeiDong LiBingbing WangXiaodong WangWilhelm BeckerInstitute of Applied Physics and Computational Mathematics
P.O.Box 8009 Beijing 100088China Institute of Theoretical Physics and Department of Physics
Shanxi University Taiyuan 030006China Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088China Institute of Theoretical Physics and Department of Physics Shanxi University Taiyuan 030006China Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of Physics Chinese Academy of Sciences Beijing 100190 China College of Physics and Electronic Engineering Northwest Normal University Lanzhou730070 China Max Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy Max-Born-Strasse2a12489 Berlin Germany
This article was originally published online on 29 May 2014 with an error in the placement of text on pages 3 and 4. The text should have appeared as below:
This article was originally published online on 29 May 2014 with an error in the placement of text on pages 3 and 4. The text should have appeared as below:
We study the evolution of magnetic structures driven by a synthetic spin-orbit coupling in a one-dimensional two-component Bose-Hubbard model. In addition to the Mott insulator-superfluid transition, in the Mott insul...
We study the evolution of magnetic structures driven by a synthetic spin-orbit coupling in a one-dimensional two-component Bose-Hubbard model. In addition to the Mott insulator-superfluid transition, in the Mott insulator phases we found a transition from a gapped ferromagnetic phase to a gapless chiral phase by increasing the strength of the spin-orbit coupling. Further increasing the spin-orbit coupling drives a transition from the gapless chiral phase to a gapped antiferromagnetic phase. These magnetic structures persist in superfluid phases. In particular, in the chiral Mott insulator and chiral superfluid phases, incommensurability is observed in characteristic correlation functions. These unconventional Mott insulator phase and superfluid phase demonstrate the different effects arising from the competition between the kinetic energy and the spin-orbit coupling.
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