Cottam Michael G, Hussain Bushra
Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7, Canada.
Department of Natural Sciences, University of Michigan, Dearborn, MI 48197, USA.
Nanomaterials (Basel). 2025 May 20;15(10):768. doi: 10.3390/nano15100768.
The spin wave renormalization processes in two-dimensional van der Waals ferromagnetic monolayers are investigated using an established non-bosonic diagram technique based on the drone-fermion perturbation method. The aim is to evaluate the damping of the long-wavelength spin wave modes at temperatures below the Curie temperature. In addition to the multi-magnon scattering processes, which typically dominate at low temperatures, an additional mechanism is found here that becomes important at elevated temperatures. This spin disorder damping mechanism, which was mainly studied previously in bulk magnetic materials and thicker films, features a spin wave or magnon being scattered by the magnetic disorder that is present when a longitudinal spin component undergoes large thermal fluctuations. The magnetic ordering in the monolayers is stabilized by an out-of-plane single-ion or Ising-type anisotropy, which influences the damping properties. Numerical results are derived for monolayer films of the van der Waals ferromagnet CrGeTe.
利用基于无自旋费米子微扰法的成熟非玻色子图技术，研究了二维范德华铁磁单层中的自旋波重整化过程。目的是评估居里温度以下温度下长波长自旋波模式的阻尼。除了通常在低温下占主导的多磁振子散射过程外，这里还发现了一种在高温下变得重要的额外机制。这种自旋无序阻尼机制主要在体磁材料和较厚薄膜中进行过研究，其特征是当纵向自旋分量经历大的热涨落时，自旋波或磁振子被存在的磁无序散射。单层中的磁有序由面外单离子或伊辛型各向异性稳定，这会影响阻尼特性。得出了范德华铁磁体CrGeTe单层膜的数值结果。
