Atomistic Spin Dynamics

This book covers theoretical and practical aspects of the vibrant and emerging research field of magnetization dynamics.

Author: Olle Eriksson

Publisher: Oxford University Press

ISBN: 9780198788669

Category: Science

Page: 256

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The purpose of this book is to provide a theoretical foundation and an understanding of atomistic spin-dynamics (ASD), and to give examples of where the atomistic Landau-Lifshitz-Gilbert equation can and should be used. As argued in the text, a description of magnetism in an atomistic way is very natural and allows for an interpretation of experimental results in a clear and deep way. This description also allows for calculations, from first principles, of all parameters needed to perform the spin-dynamics simulations, without using experimental results as input to the simulations. As shown in the book, we are now at a very exciting situation, where it is possible to perform accurate and efficient atomistic simulations on a length- and time-scale which is balancing on the edge of what is experimentally possible. In this way, ASD simulations can both validate and be validated by state-of-the art experiments, and ASD simulations also have the possibility to act as a predictive tool that is able to explain the magnetization dynamics in experimentally inaccessible situations. The purpose of this book has been to communicate technically relevant concepts. An even larger motivation is to communicate an inspiration to magnetism and magnetization dynamics, and the emerging technological fields that one may foresee, e.g. in magnonics, solitonics and skyrmionics.
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Electron Nuclear Spin Dynamics in Semiconductor Nanostructures

Electron-nuclear spin dynamics of Ga2+ paramagnetic centers probed by
spindependent recombination: A master equation approach. Phys. Rev. B, 95 ...
Atomistic spin-orbit coupling and k·p parameters in III-V semiconductors. Phys.
Rev.

Author: M. M. Glazov

Publisher: Oxford University Press

ISBN: 9780192534217

Category: Science

Page: 320

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In recent years, the physics community has experienced a revival of interest in spin effects in solid state systems. On one hand, the solid state systems, particularly, semiconductors and semiconductor nanosystems, allow us to perform benchtop studies of quantum and relativistic phenomena. On the other hand, this interest is supported by the prospects of realizing spin-based electronics, where the electron or nuclear spins may play a role of quantum or classical information carriers. This book looks in detail at the physics of interacting systems of electron and nuclear spins in semiconductors, with particular emphasis on low-dimensional structures. These two spin systems naturally appear in practically all widespread semiconductor compounds. The hyperfine interaction of the charge carriers and nuclear spins is particularly prominent in nanosystems due to the localization of the charge carriers, and gives rise to spin exchange between these two systems and a whole range of beautiful and complex physics of manybody and nonlinear systems. As a result, understanding of the intertwined spin systems of electrons and nuclei is crucial for in-depth studying and controlling the spin phenomena in semiconductors. The book addresses a number of the most prominent effects taking place in semiconductor nanosystems including hyperfine interaction, nuclear magnetic resonance, dynamical nuclear polarization, spin-Faraday and spin-Kerr effects, processes of electron spin decoherence and relaxation, effects of electron spin precession mode-locking and frequency focussing, as well as fluctuations of electron and nuclear spins.
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Oxford Handbook of Nanoscience and Technology

A much less explored area is that of atomistic simulations of magnetodynamics.
These, however ... Within this framework the theoretical foundation for time-
dependent DFT for spin-dynamics was laid several years ago (Liu et al. 1989;
Capelle ...

Author: A. V. Narlikar

Publisher: OUP Oxford

ISBN: 9780199533046

Category: Technology & Engineering

Page: 920

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These three volumes are intended to shape the field of nanoscience and technology and will serve as an essential point of reference for cutting-edge research in the field.
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Ultrafast Magnetism I

This volume on Ultrafast Magnetism is a collection of articles presented at the international “Ultrafast Magnetization Conference” held at the Congress Center in Strasbourg, France, from October 28th to November 1st, 2013.

Author: Jean-Yves Bigot

Publisher: Springer

ISBN: 9783319077437

Category: Science

Page: 341

View: 414

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This volume on Ultrafast Magnetism is a collection of articles presented at the international “Ultrafast Magnetization Conference” held at the Congress Center in Strasbourg, France, from October 28th to November 1st, 2013. This first conference, which is intended to be held every two years, received a wonderful attendance and gathered scientists from 27 countries in the field of Femtomagnetism, encompassing many theoretical and experimental research subjects related to the spins dynamics in bulk or nanostructured materials. The participants appreciated this unique opportunity for discussing new ideas and debating on various physical interpretations of the reported phenomena. The format of a single session with many oral contributions as well as extensive time for poster presentations allowed researchers to have a detailed overview of the field. Importantly, one could sense that, in addition to studying fundamental magnetic phenomena, ultrafast magnetism has entered in a phase where applied physics and engineering are playing an important role. Several devices are being proposed with exciting R&D perspectives in the near future, in particular for magnetic recording, time resolved magnetic imaging and spin polarized transport, therefore establishing connections between various aspects of modern magnetism. Simultaneously, the diversity of techniques and experimental configurations has flourished during the past years, employing in particular Xrays, visible, infra-red and terahertz radiations. It was also obvious that an important effort is being made for tracking the dynamics of spins and magnetic domains at the nanometer scale, opening the pathway to exciting future developments. The concerted efforts between theoretical and experimental approaches for explaining the dynamical behaviors of angular momentum and energy levels, on different classes of magnetic materials, are worth pointing out. Finally it was unanimously recognized that the quality of the scientific oral and poster presentations contributed to bring the conference to a very high international standard.
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Atomistic Simulation of Collective Excitations in Bcc Iron with Vacancy Defects

Utilizing an atomistic computational model which handles both translational and spin degrees of freedom, we have performed combined molecular and spin dynamics simulations to investigate the effect of vacancy defects on spin and lattice ...

Author: Mark Stephen Mudrick

Publisher:

ISBN: OCLC:1050111083

Category:

Page: 178

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Utilizing an atomistic computational model which handles both translational and spin degrees of freedom, we have performed combined molecular and spin dynamics simulations to investigate the effect of vacancy defects on spin and lattice excitations in ferromagnetic iron. Interatomic interactions are described using an embedded atom potential and magnetic interactions are governed by a Heisenberg-like Hamiltonian with a coordinate dependent exchange interaction. Fourier transforms of space and time-displaced correlation functions yield the dynamic structure factor, providing characteristic frequencies and lifetimes of the spin wave modes. Comparison of the system containing a 5% randomly distributed vacancy concentration with pure lattice data shows a decrease in frequency as well as a decrease in lifetime for all accessible transverse spin wave excitations. By constructing the spin wave dispersion curve, we observe a decrease in the spin wave stiffness parameter with the introduction of vacancy defects, in agreement with experimental neutron scattering data. Additionally, a rugged spin wave line shape for low-$q$ excitations indicates the presence of multiple localized modes near the defect sites. These induced excitations result in reduced excitation lifetimes due to increased magnon-magnon scattering. We observe further evidence of increased magnon-magnon scattering as additional two-spin-wave annihilation peaks appear in the longitudinal spin wave spectrum under these conditions of impurity. Single vacancy defects, or voids, of varying sizes are introduced into the system, resulting in sharp splitting of long-wavelength excitation line shapes. This splitting behavior is shown to be strongly affected by defect size as well as the size of the surrounding system. Localized correlation function measurements are made in the vicinity of the defect site, showing the existence of a dominant excitation mode in this region. The longitudinal magnetic excitation spectrum contains additional modes which are not present in the pure system due to the increased number of available spin wave annihilation processes. The longitudinal spectrum also reveals splitting of the magnon-phonon coupling mode caused by the defect center.
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Topological Magnon Materials and Transverse Magnon Transport

Solid state physics; Magnons; Spin waves; Topological insulator; Topological semimetal; Hall effect; Spin dynamics; Kubo formula; Skyrmions

Author: Alexander Mook

Publisher:

ISBN: OCLC:1006498900

Category:

Page:

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Solid state physics; Magnons; Spin waves; Topological insulator; Topological semimetal; Hall effect; Spin dynamics; Kubo formula; Skyrmions
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Neutron Spin Echo in Polymer Systems

3 Large Scale Dynamics of Homopolymers In general , flexible long chain
polymers easily form rotational isomers at the bonds of the chain along the ... We
compare the NSE rheological results with atomistic molecular dynamic
simulations .

Author: Dieter Richter

Publisher: Springer Science & Business Media

ISBN: 3540228624

Category: Technology & Engineering

Page: 246

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1 Introduction.- 2 Neutron Scattering and Neutron Spin Echo.- 3 Large Scale Dynamics of Homopolymers.-
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Master Equation Models of Macromolecular Dynamics from Atomistic Simulation

[ 131 ] for an early exposition of this method as applied to the analysis of Monte
Carlo simulations of spin systems , Swope et al . [ 178 ] for the analysis of
molecular dynamics simulations , or Janke [ 88 ] for a recent general illustration .

Author: John D. Chodera

Publisher:

ISBN: UCAL:X85387

Category:

Page: 143

View: 767

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This dissertation is concerned with the construction, validation, and use of master equation models for the study of macromolecular conformational dynamics. The master equation formalism is a powerful tool for describing the dynamics of a system that can be characterized by a discrete-state, continuous-time Markov process. Once constructed from a large quantities of short trajectories, the evolution of experimentally measurable dynamical observables can be computed and compared with experiment. Additionally, information not yet directly accessible to experiment but which may be useful in aiding understanding or the generation of novel hypotheses, such as folding pathways, transiently populated conformations, and mean first passage times, can also be easily obtained. We demonstrate that a master equation model constructed from short trajectories can describe slow conformational dynamics for a solvated alanine peptide over long times, propose a number of tests to tell whether a model constructed from short trajectories will adequately describe dynamics over long times, and describe an algorithm for the automatic construction of these models from simulation data. While the focus here is on protein folding and dynamics, these techniques are very general, and can be broadly applied to problems in biomolecular dynamics.
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Condensed Matter Theories

Control of Quantum Many - Body Dynamics , 3-22 Core - Ionization
Spectroscopies and Decay Processes , 377-388 Correlation ... Harmonics and ,
485-506 A Ab - Initio Spin Dynamics and Magneto Optics , 127-136 Alpha Cluster
Super - deformation : Alpha - planar states ... 341-352 Atomic and Molecular
Systems , 377406 Atomic Electron Correlation and Particle and Anti - Particle
Atomistic Simulation ...

Author: Eduardo V. Ludeña

Publisher: Nova Science Pub Incorporated

ISBN: CORNELL:31924077641953

Category: Science

Page: 534

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Condensed Matter Theories Volume 11
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Dynamics of Supercooled Liquids

On the left are spin - facilitated models ( 93 , 94 ] . Instead of keeping track of
particles , they model the constrained dynamics of mobility fields and are thought
to arise from coarse graining atomistic models like the one depicted on the right ...

Author: Albert Chun Pan

Publisher:

ISBN: UCAL:C3503345

Category:

Page: 254

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Electron Microscopy and Multiscale Modeling

This shows that the total energy of the system remains constant while the
individual energies of the lattice or the spin subsystems vary as a function of time
. ... considering the time derivative of the total angular momentum of the system 2,
1 , e ; ( 1 ) we find that for pure spin dynamics this quantity is also conserved . ...
In terms of the general methodology of atomistic simulations this is a very
unusual point .

Author: Anatoly Avilov

Publisher: Amer Inst of Physics

ISBN: UCSD:31822035537174

Category: Science

Page: 300

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The EMMM-2007 Conference brought together leading experts in electron microscopy and materials modeling from around the world to explore how to synergistically combine atomic scale characterization and modeling to enhance the development of new materials.
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Chemical Modelling

Here, the focus is on atomistic molecular simulation, with a focus on proteins, and
a particular emphasis on the area of ... (and also in the analysis of NMR data on
spin relaxation7 and dynamics, for example dynamics of protein sidechains8).

Author: Alan Hinchliffe

Publisher: Royal Society of Chemistry

ISBN: 9780854042432

Category: Reference

Page: 542

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Chemical Modelling; Applications and Theory comprises critical literature reviews of all aspects of molecular modelling. Molecular modelling in this context refers to modelling the structure properties and reactions of atoms molecules and materials. Each chapter provides a selective review of recent literature, incorporating sufficient historical perspective for the non-specialist to gain an understanding. With chemical modelling covering such a wide range of subjects this Specialist Periodical Report serves as the first port of call to any chemist, biochemist, materials scientist or molecular physicist needing to acquaint themselves with major developments in the area. Volume 4 provides a review of the literature published from June 2003 to May 2005.
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Renormalization Group Theory

Atomistic theories such as classical spin wave theory of magnetism or
conventional theory of lattice dynamics usually neglect the energy degrees of
freedom of the infinite solid. The dynamics of the infinite solid is due to bosons,
GSW bosons ...

Author: Ulrich Köbler

Publisher: Springer Science & Business Media

ISBN: 9783642024887

Category: Technology & Engineering

Page: 394

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Spin wave theory of magnetism and BCS theory of superconductivity are typical theories of the time before renormalization group (RG) theory. The two theories consider atomistic interactions only and ignore the energy degrees of freedom of the continuous (infinite) solid. Since the pioneering work of Kenneth G. Wilson (Nobel Prize of physics in 1982) we know that the continuous solid is characterized by a particular symmetry: invariance with respect to transformations of the length scale. Associated with this symmetry are particular field particles with characteristic excitation spectra. In diamagnetic solids these are the well known Debye bosons. This book reviews experimental work on solid state physics of the last five decades and shows in a phenomenological way that the dynamics of ordered magnets and conventional superconductors is controlled by the field particles of the infinite solid and not by magnons and Cooper pairs, respectively. In the case of ordered magnets the relevant field particles are called GSW bosons after Goldstone, Salam and Weinberg and in the case of superconductors the relevant field particles are called SC bosons. One can imagine these bosons as magnetic density waves or charge density waves, respectively. Crossover from atomistic exchange interactions to the excitations of the infinite solid occurs because the GSW bosons have generally lower excitation energies than the atomistic magnons. According to the principle of relevance the dynamics is governed by the excitations with the lowest energy. The non relevant atomistic interactions with higher energy are practically unimportant for the dynamics.
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Physics Briefs

... spin resonance Magnetism and spin dynamics in MnPS , and pyridine
intercalated MnPSg : An electron paramagnetic ... homogeneous nucleation in
multicompo nent systems 14-81598 INTERFACES : computer codes Atomistic
modelling ...

Author:

Publisher:

ISBN: UOM:39015027832933

Category: Physics

Page:

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