Zhang Quan, Zhang Yang, Li Ying, Fang Dangqi, Che Junwei, Zhang Erhu, Zhang Peng, Zhang Shengli
MOE Key Lab for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, China.
Phys Chem Chem Phys. 2022 Mar 16;24(11):7077-7083. doi: 10.1039/d2cp00010e.
In spintronics, the embodiment of abundance availability, long spin relaxation time, complete spin-polarization and high Curie temperature () in intrinsic metal-free half-metallic ferromagnets (MFHMFs) are highly desirable and challenging. In this work, employing density functional theory, we first propose a dynamically, thermally, and mechanically stable two-dimensional (2D) intrinsic MFHMF, a MoS-like PN monolayer, which possesses not only completely spin-polarized half-metallicity, but also an above-room-temperature (385 K). The half-metallic gap is calculated to be 1.70 eV, which can effectively prevent the spin-flip transition caused by thermal agitation. The mechanism of magnetism in the PN monolayer is mainly derived from the electron direct exchange interaction that separates from usual d-state magnetic materials. Moreover, the robustness of the ferromagnetism and half-metallicity is observed against an external strain and carrier (electron or hole) doping. Surprisingly, electron doping can effectively increase the Curie temperature of the PN monolayer. The proposed research work provides an insight that PN can be a promising candidate for realistic room-temperature metal-free spintronic applications.
在自旋电子学中，本征无金属半金属铁磁体（MFHMFs）具备丰富的可利用性、长自旋弛豫时间、完全的自旋极化以及高居里温度（），这些特性备受期待但也颇具挑战性。在这项工作中，我们运用密度泛函理论，首次提出了一种动态、热和机械稳定的二维（2D）本征MFHMF，即类MoS的PN单层，它不仅具有完全自旋极化的半金属性，而且居里温度高于室温（385 K）。计算得出半金属能隙为1.70 eV，这可以有效防止由热搅动引起的自旋翻转转变。PN单层中的磁性机制主要源自与常见d态磁性材料不同的电子直接交换相互作用。此外，观察到铁磁性和半金属性对外加应变和载流子（电子或空穴）掺杂具有鲁棒性。令人惊讶的是，电子掺杂可以有效提高PN单层的居里温度。所提出的研究工作提供了一种见解，即PN有望成为实际室温无金属自旋电子学应用的候选材料。
