发表机构
School of Physics and Optoelectronics, Shandong Normal University（山东师范大学物理与光电学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究以二维铁磁1T-FeX2单层为对象，通过计算揭示超交换与直接交换分别稳定半金属和半导体态，并阐明MIT附近交换临界行为及居里温度变化，为二维器件设计提供指导。
AI 中文摘要
在快速增长的二维（2D）材料家族中，二维铁磁（FM）材料近来引起了广泛关注。二维铁磁材料中的铁磁性源于其内在的交换相互作用。特别是，通过多种调控策略在二维铁磁材料中诱导的金属-绝缘体转变（MITs）对于设计尺寸更小的二维电子器件（如晶体管）至关重要。然而，交换相互作用的临界行为及其对MIT附近居里温度的影响仍有待阐明。以二维铁磁1T-FeX2（X=Cl, Br, I）单层为测试平台，我们通过计算研究了在位库仑电子-电子相互作用驱动的MIT附近交换相互作用的临界行为。研究发现，铁磁超交换相互作用和直接交换相互作用分别在能量上有利于半金属态和半导体态。此外，半金属态具有更强的铁磁耦合，因而具有更高的居里温度。本研究提供了对MIT与交换相互作用之间相互关系的全面理解，并可能有助于需要同时利用MIT和与交换相互作用相关的磁性质（特别是强磁有序和更高居里温度）的二维铁磁材料器件设计。
英文摘要
Within the rapidly growing family of two-dimensional (2D) materials, 2D ferromagnetic (FM) materials have attracted a great deal of recent attention. The ferromagnetism in 2D FM materials originates from the underlying exchange interactions. In particular, metal-insulator transitions (MITs) in 2D FM materials induced via various modulation strategies is critical to the design of 2D electronic devices with reduced sizes (e.g. transistor). However, the critical behaviors of exchange interactions and their effects on the Curie temperatures near MITs remains to be clarified. By taking the 2D FM 1T-FeX2 (X=Cl, Br, I) monolayers as the testbeds, we computationally study the critical behaviors of the exchange interactions in the vicinity of the MITs driven by the on-site Coulomb electron-electon interactions. The FM superexchange interactions and the direct exchange interactions are found to energetically favor the halfmetallic and semiconducting states, respectively. In addition, the halfmetallic states have the stronger FM couplings and thus the higher Curie temperatures. This study provides a comprehensive understanding of the interrelations between MITs and exchange interactions and could be useful for the device design requiring both MITs and exchange-interaction related magnetic properties, particularly robust magnetic ordering and higher Curie temperatures, in 2D FM materials.
