Fast and robust algorithm for energy minimization of spin systems applied in an analysis of high temperature spin configurations in terms of skyrmion density

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-03
Major/Subject
Mcode
Degree programme
Language
en
Pages
11
Series
Computer Physics Communications, Volume 260
Abstract
An algorithm for the minimization of the energy of magnetic systems is presented and applied to the analysis of thermal configurations of a ferromagnet to identify inherent structures, i.e. the nearest local energy minima, as a function of temperature. Over a rather narrow temperature interval, skyrmions appear and reach a high temperature limit for the skyrmion density. In addition, the performance of the algorithm is further demonstrated in a self-consistent field calculation of a skyrmion in an itinerant magnet. The algorithm is based on a geometric approach in which the curvature of the spherical domain is taken into account and as a result the length of the magnetic moments is preserved in every iteration. In the limit of infinitesimal rotations, the minimization path coincides with that obtained using damped spin dynamics while the use of limited-memory quasi-newton minimization algorithms, such as the limited-memory Broyden–Fletcher–Goldfarb–Shanno (LBFGS) algorithm, significantly accelerates the convergence.
Description
Keywords
Itinerant magnets, Magnetism, Skyrmions, Spin minimization
Other note
Citation
Ivanov, A V, Uzdin, V M & Jónsson, H 2021, ' Fast and robust algorithm for energy minimization of spin systems applied in an analysis of high temperature spin configurations in terms of skyrmion density ', Computer Physics Communications, vol. 260, 107749 . https://doi.org/10.1016/j.cpc.2020.107749