Yu Maolin, Liu Xiaofei, Guo Wanlin
State Key Laboratory of Mechanics and Control of Mechanical Structures and Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Phys Chem Chem Phys. 2018 Feb 28;20(9):6374-6382. doi: 10.1039/c7cp07912e.
Ga-based two-dimensional transition-metal trichalcogenides with tunable ferromagnetic semiconducting properties are explored by first-principles calculations. It is found that the CrGaTe monolayer is an intrinsic ferromagnetic semiconductor with an indirect bandgap of 0.3 eV and exhibits strong dynamical, thermal and mechanical stabilities in the free-standing form. Its Curie temperature of 71 K estimated by Monte Carlo simulations can be significantly enhanced up to near room-temperature (263 K) by 5% biaxial tensile strain at which its structure still remains dynamically stable, while compressive strain can turn the monolayer from a ferromagnetic semiconductor to an antiferromagnetic semiconductor and finally to a ferromagnetic metal with a Curie temperature of 473 K at -5% strain. It is revealed that the pronounced strain tunability originates from the competition between a variety of magnetic exchange interactions. The CrGaSe monolayer is found to exhibit similar intrinsic ferromagnetic semiconducting properties and strain tunability. The exceptional properties render Ga-based transition-metal trichalcogenides promising candidates for spintronic applications.
通过第一性原理计算探索了具有可调铁磁半导体特性的基于镓的二维过渡金属三卤化物。研究发现，CrGaTe单层是一种本征铁磁半导体，间接带隙为0.3 eV，以独立形式表现出很强的动力学、热稳定性和机械稳定性。通过蒙特卡罗模拟估计，其居里温度为71 K，在5%的双轴拉伸应变下，居里温度可显著提高到接近室温（263 K），此时其结构仍保持动态稳定，而压缩应变可使单层从铁磁半导体转变为反铁磁半导体，最终在-5%应变下转变为居里温度为473 K的铁磁金属。研究表明，显著的应变可调性源于多种磁交换相互作用之间的竞争。发现CrGaSe单层表现出类似的本征铁磁半导体特性和应变可调性。这些优异的特性使基于镓的过渡金属三卤化物成为自旋电子学应用的有前途的候选材料。
