1. 2D ferromagnetism at finite temperatures under quantum scrutiny
- Author
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Vanherck, Joren, Bacaksiz, Cihan, Sorée, Bart, Milošević, Milorad V., and Magnus, Wim
- Subjects
Condensed Matter - Statistical Mechanics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
Recent years have seen a tremendous rise of two-dimensional (2D) magnetic materials, several of which verified experimentally. However, most of the theoretical predictions to date rely on ab-initio methods, at zero temperature and fluctuations-free, while one certainly expects detrimental quantum fluctuations at finite temperatures. Here we present the solution of the quantum Heisenberg model for honeycomb/hexagonal lattices with anisotropic exchange interaction up to third nearest neighbors and in an applied field in arbitrary direction, that answers the question whether long-range magnetization can indeed survive in the ultrathin limit of materials, up to which temperature, and what the characteristic excitation (magnon) frequencies are, all essential to envisaged applications of magnetic 2D materials. We find that long-range magnetic order persists at finite temperature for materials with overall easy-axis anisotropy. We validate the calculations on the examples of monolayer CrI3, CrBr3 and MnSe2. Moreover, we provide an easy-to-use tool to calculate Curie temperatures of new 2D computational materials., Comment: 14 pages, 5 figures. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 117, 052401 (2020) and may be found at https://doi.org/10.1063/5.0015619 more...
- Published
- 2020
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