反铁磁性
凝聚态物理
静水压力
范德瓦尔斯力
物理
挫折感
基态
伊辛模型
材料科学
热力学
量子力学
分子
作者
Jesse Kapeghian,Danila Amoroso,Connor A. Occhialini,Luiz G. P. Martins,Qian Song,Jesse S. Smith,Joshua J. Sanchez,Jing Kong,Riccardo Comin,Paolo Barone,Bertrand Dupé,Matthieu J. Verstraete,Antía S. Botana
出处
期刊:Physical review
日期:2024-01-03
卷期号:109 (1)
标识
DOI:10.1103/physrevb.109.014403
摘要
Transition metal dihalides have recently garnered interest in the context of two-dimensional van der Waals magnets as their underlying geometrically frustrated triangular lattice leads to interesting competing exchange interactions. In particular, ${\mathrm{NiI}}_{2}$ is a magnetic semiconductor that has been long known for its exotic helimagnetism in the bulk. Recent experiments have shown that the helimagnetic state survives down to the monolayer limit with a layer-dependent magnetic transition temperature that suggests a relevant role of the interlayer coupling. Here, we explore the effects of hydrostatic pressure as a means to enhance this interlayer exchange and ultimately tune the electronic and magnetic response of ${\mathrm{NiI}}_{2}$. We study first the evolution of the structural parameters as a function of external pressure using first-principles calculations combined with x-ray diffraction measurements. We then examine the evolution of the electronic structure and magnetic exchange interactions via first-principles calculations and Monte Carlo simulations. We find that the leading interlayer coupling is an antiferromagnetic second-nearest-neighbor interaction that increases monotonically with pressure. The ratio between isotropic third- and first-nearest-neighbor intralayer exchanges, which controls the magnetic frustration and determines the magnetic propagation vector $\mathbf{q}$ of the helimagnetic ground state, is also enhanced by pressure. As a consequence, our Monte Carlo simulations show a monotonic increase in the magnetic transition temperature, indicating that pressure is an effective means to tune the magnetic response of ${\mathrm{NiI}}_{2}$.
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