据悉，原生铁性，包括铁电性和铁磁性，是物质的基本物理特性。多铁性材料在单一相中同时存在多种铁序，为磁电耦合提供了便利途径。然而，磁性和极性之间的权衡仍然是一个挑战，这限制了在多铁性材料中实现磁电交叉控制的可能性。
本文提出了一种替代策略，即所谓的变铁性，以规避磁电排他性，这种变铁性表现出多个但不共存的铁序。磁性和极性之间的自然排斥是多铁性不可克服的弱点，而变铁性则具有明显的优势，使其成为固有强磁电的天然富矿。设计变铁材料的一般规则取决于共价体系中声子和电子结构不稳定性之间的竞争关系。通过基于初级密度泛函理论的计算，研究人员预测钛基三硫化物具有独特的跷跷板型磁电特性，使其成为变铁性的候选化合物。这种变铁性，作为铁性家族的一个新兴分支，重塑了磁电的框架，超出了基于多铁性的既定场景。
附：英文原文
Title: Alterferroicity with seesaw-type magnetoelectricity
Author: Wang, Ziwen, Dong, Shuai
Issue&Volume: 2023-11-28
Abstract: Primary ferroicities like ferroelectricity and ferromagnetism are essential physical properties of matter. Multiferroics, with coexisting multiple ferroic orders in a single phase, provide a convenient route to magnetoelectricity. Even so, the general trade-off between magnetism and polarity remains inevitable, which prevents practicable magnetoelectric cross-control in the multiferroic framework. Here, an alternative strategy, i.e., the so-called alterferroicity, is proposed to circumvent the magnetoelectric exclusiveness, which exhibits multiple but noncoexisting ferroic orders. The natural exclusion between magnetism and polarity, as an insurmountable weakness of multiferroicity, becomes a distinct advantage in alterferroicity, making it an inborn rich ore for intrinsic strong magnetoelectricity. The general design rules for alterferroic materials rely on the competition between the instabilities of phononic and electronic structures in covalent systems. Based on primary density functional theory calculations, Ti-based trichalcogenides are predicted to be alterferroic candidates, which exhibit unique seesaw-type magnetoelectricity. This alterferroicity, as an emerging branch of the ferroic family, reshapes the framework of magnetoelectricity, going beyond the established scenario based on multiferroicity.
DOI: 10.1073/pnas.2305197120
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2305197120