Sun Caijia, Ye Haoshen, Zhu Yijie, Chen Leiming, Bai Dongmei, Wang Jianli
School of Materials and Physics, China University of Mining and Technology, Xuzhou 221116, China.
Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing 211189, China.
Nanoscale. 2024 Aug 22;16(33):15746-15757. doi: 10.1039/d4nr01441c.
The vertical integration of a ferromagnetic monolayer and a ferroelectric monolayer into van der Waals heterostructures offers a promising route to achieve two-dimensional multiferroic semiconductors owing to the lack of intrinsic single-phase multiferroic materials in nature. In this study, we propose a VNH/AlO van der Waals magnetoelectric multiferroic heterostructure and investigate its electronic, magnetic, and transport properties using density functional theory combined with the Boltzmann transport theory. The VNH monolayer is a room-temperature ferromagnetic semiconductor with a band gap of 0.24 eV and a Curie temperature of 411 K, while the AlO monolayer is a ferroelectric semiconductor with a polarization value of 0.11 C m. In the VNH/AlO van der Waals heterostructures, the conversion between the metal and the semiconductor can be controlled by altering the polarization of the AlO layer. The VNH/AlO van der Waals heterostructure retains room-temperature ferromagnetism, and the reverse of polarization is accompanied with a change in the direction of the easy magnetization axis. In addition, electrostatic doping can significantly improve the conductivity of the downward polarization state and transform the upward polarization state from a metal to a half-metal, achieving 100% spin polarization. Our results thus pave the way for achieving highly tunable electromagnetic and transport properties in van der Waals magnetoelectric heterostructures, which have potential applications in next-generation low-power logic and memory devices.
由于自然界中缺乏本征单相多铁性材料，将铁磁单层和铁电单层垂直整合到范德华异质结构中为实现二维多铁性半导体提供了一条很有前景的途径。在本研究中，我们提出了一种VNH/AlO范德华磁电多铁性异质结构，并结合玻尔兹曼输运理论，使用密度泛函理论研究其电子、磁性和输运性质。VNH单层是一种室温铁磁半导体，带隙为0.24 eV，居里温度为411 K，而AlO单层是一种极化值为0.11 C/m的铁电半导体。在VNH/AlO范德华异质结构中，金属与半导体之间的转变可通过改变AlO层的极化来控制。VNH/AlO范德华异质结构保留室温铁磁性，极化反转伴随着易磁化轴方向的改变。此外，静电掺杂可显著提高向下极化态的电导率，并将向上极化态从金属转变为半金属，实现100%的自旋极化。因此，我们的结果为在范德华磁电异质结构中实现高度可调的电磁和输运性质铺平了道路，这些异质结构在下一代低功耗逻辑和存储器件中具有潜在应用。
