Modulation of magnetism in transition-metal-doped two-dimensional GeS

作者：Zhang, Chunxiao^*; Yang, Baoyong; Tang, Chao; He, Chaoyu; Li, Jin; Ouyang, Tao; Zhong, Jianxin

来源：Journal of Physics D: Applied Physics , 2018, 51(22): 225001.

DOI：10.1088/1361-6463/aabd96

• germanium monosulfide
• transition metal
• magnetism
• crystal field splitting
• spin exchange splitting
• spin crossover

Two-dimensional (2D) germanium monosulfide (GeS) is a promising nanoelectronic material with a desirable band gap, high carrier mobility, and anisotropic structures. In this work, we present a density functional theory study on the magnetism of 3d TM (TM = Fe, Co and Ni)-doped 2D GeS. We find that the TM atoms strongly bond to the GeS sheet with quite sizable binding energies due to the sp(3)-like hybridization of 2D GeS. The Fe- and Co-doped GeS show nonzero magnetic ground states. Hubbard parameter U hardly affects the magnetic moment when U is no more than 6 eV. In particular, substitutional Fe (Fe@GeS) and substitutional Co (Co@GeS) present high-spin states with 4 mu(B) and 3 mu(B). The magnetism of TM-doped 2D GeS mainly arises from the crystal field splitting and spin exchange splitting of TM-3d orbitals. The magnetic and electronic properties of the Fe@GeS and Co@GeS systems can be easily controlled in a small vertical external electric field (E-ext). The underlying mechanism of spin crossover is that E-ext affects the crystal field splitting and then shifts the relative positions of 3d orbitals, which tunes the spin configurations. These results render monolayer GeS a promising 2D material for applications in future spintronics.

• 出版日期2018-6-6
• 单位湘潭大学