2013/04/24 by Stefan Buhrandt, Lars Fritz · 193 citations
Mathematics · Physics and Astronomy · #Classical XY model #Condensed matter physics #Gaussian #Lattice (music) #Magnet #Magnetic properties of thin films #Mathematics #Monte Carlo method #Paramagnetism #Phase (matter) #Phase diagram #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Skyrmion #Statistical physics #Theoretical and Computational Physics #Thermal #Thermal fluctuations #Thermodynamics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.88.195137
published in Physical Review B 88(19) (American Physical Society) · 6 pages, 3 figures
arxiv created 2013/04/24 · openalex publication_date 2013/11/20 · arxiv updated 2013/11/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Chiral magnets, such as MnSi, display a rich finite temperature phase diagram in an applied magnetic field. The most unusual of the phases encountered is the so-called A Phase characterized by a triangular lattice of skyrmion tubes. Its existence cannot be captured within a mean-field treatment of a Landau-Ginzburg functional, but thermal fluctuations to Gaussian order are required to stabilize it. In this paper, we go beyond Gaussian order in a fully nonperturbative study of a three-dimensional lattice spin model using classical Monte Carlo simulations. We demonstrate that the A Phase is, indeed, stabilized by thermal fluctuations, and furthermore, we reproduce the full phase diagram found in experiments. The thermodynamic signatures of the helimagnetic transition upon cooling from the paramagnet are qualitatively consistent with experimental findings and lend further support to the Brazovski\ifmmode \breve\imath\else \u\i\fi scenario, which describes a fluctuation-driven first-order transition due to the abundance of soft modes.