Prediction of two-dimensional antiferromagnetic ferroelasticity in an AgF₂ monolayer

Abstract

<p>Two-dimensional multiferroics, harboring antiferromagneticity and ferroelasticity simultaneously, is essential and highly sought for miniaturized device applications, such as high-density data storage, but so far it is rarely explored. Herein, using...</p>

New Ideas for Understanding the Structure and Magnetism in AgF2: Prediction of Ferroelasticity

“…In the same study, Xu et al. [16] find that in their free‐standing configuration each individual AgF 2 sheet is still buckled but, due to the JT effect, they undergo a cooperative deformation into one of three equivalent minima separated by small energy barriers that provides the system with ferroelastic properties. Combined with the inherent anti‐ferromagnetism of the system, they showed that bidimensional AgF 2 is a multiferroic material.…”

“…Systematic analyses of the magnetic structure [5] indicate that flattening the geometry of these slabs would reinforce the AFM coupling allowing that found in the parent material of high‐Tc, La 2 CuO 4 to be surpassed. Moreover, based on first‐principles simulations, it has been proposed [16] that these layers are surprisingly bound by weak van der Waals interactions with a cleavage energy that is comparable to that of graphite and, as a consequence, they should be easily exfoliable. In the same study, Xu et al [16] .…”

“…Moreover, based on first‐principles simulations, it has been proposed [16] that these layers are surprisingly bound by weak van der Waals interactions with a cleavage energy that is comparable to that of graphite and, as a consequence, they should be easily exfoliable. In the same study, Xu et al [16] . find that in their free‐standing configuration each individual AgF 2 sheet is still buckled but, due to the JT effect, they undergo a cooperative deformation into one of three equivalent minima separated by small energy barriers that provides the system with ferroelastic properties.…”

“…On the other hand, the claims of van der Waals bonding between AgF 2 sheets seem at odds with the strong bonding expected for the crystal. In fact, it is important to note that the single AgF 2 layer studied by Xu et al [16] . is more closely related to the hexagonal structure of bulk CuCl 2 , basis of some graphite intercalation compounds (see, e. g., ref.…”

“…While previous works on AgF 2 [ 1 , 2 , 3 , 4 , 5 , 14 , 15 , 16 , 17 , 18 ] focus on the layered nature of the system and the similarities with other quasi‐bidimensional systems, like La 2 CuO 4 , there are still many open questions on the nature of the tridimensional crystal and the way the individual sheets and magnetism emerge in its bulk. For example, in layered perovskites like La 2 CuO 4 [ 19 , 20 ] magnetism is contained within CuO 2 atomic planes that are separated from each other physically by two LaO planes with certain likeness with the rock‐salt structure (Figure 1 ).…”