Skyrmion lattice phase in three-dimensional chiral magnets from Monte Carlo simulations
Skyrmion lattice phase in three-dimensional chiral magnets from Monte Carlo simulations
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DOI：
10.1103/physrevb.88.195137
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发表时间：
2013-11-20
影响因子：
3.7
通讯作者：
Fritz, Lars
中科院分区：
文献类型：
--
作者：
Buhrandt, Stefan;Fritz, Lars
手性磁体，如MnSi，在外加磁场中显示丰富的有限温度相图。遇到的最不寻常的相是所谓的A相，其特征是三角形的skyrmion管晶格。它的存在不能被捕获内的Landau-Ginzburg功能的平均场治疗，但热波动高斯秩序需要稳定it. In本文中，我们超越高斯秩序在一个完全非微扰研究的三维晶格自旋模型，使用经典的Monte Carlo模拟。我们证明，A相是，确实，稳定的热波动，此外，我们重现实验中发现的完整的相图。从顺磁体冷却后的helmagnetic过渡的热力学签名定性与实验结果一致，并提供进一步的支持Brazovskii的情况下，它描述了一个波动驱动的一阶过渡，由于丰富的软模式。
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 Brazovskii scenario, which describes a fluctuation-driven first-order transition due to the abundance of soft modes.