Tunable room-temperature ferromagnetism in the SiC monolayer

Abstract

It is essential to explore two-dimensional (2D) material with magnetic ordering in new generation spintronic devices. Particularly, the seeking of roomtemperature 2D ferromagnetic (FM) materials is a hot topic of current research. Here, we study magnetism of the Mn-doped and electron-doped SiC monolayer using first-principle calculations. For the Mn-doped SiC monolayer, we find that either electron or hole could mediate the ferromagnetism in the system and the Curie temperature (T C ) can be improved by appropriate carrier doping. The codoping strategy is also discussed on improving T C . The transition between antiferromagnetic and FM phase can be found by strain engineering. The T C is improved above room temperature (RT) under the strain larger than 0.06. Moreover, the Mn-doped SiC monolayer develops half-metal at the strain range of 0.05 − 0.1. On the other hand, the direct electron doping can induce ferromagnetism due to the van Hove singularity in density of states of the conduction band edge of the SiC monolayer. The T C is found to be around RT. These fascinating controllable electronic and magnetic properties are desired for spintronic applications.

Two-Dimensional Silicon Carbide: Emerging Direct Band Gap Semiconductor

“…There has been a great interest in understanding magnetism properties of 2D SiC and related material as well, as bulk SiC is considered one of the great candidates for magnetism and spintronic applications. Although perfect monolayer planar SiC was found to be a non-magnetic semiconductor [ 52 , 76 , 77 ], other forms of 2D SiC including defect-contained monolayer exhibits magnetism behavior [ 78 , 79 ]. Theoretical studies have found that the magnetic properties of 2D SiC can be tuned through: (i) doping, (ii) structural defects and (iii) mechanical strain, among others.…”

“…Magnetic moment in the doped materials arises from the asymmetric behavior of energy levels around fermi level in their resulting electronic structures. Variety of dopants including transition metals (TMs) [ 68 , 76 , 79 , 80 , 81 ] and non-magnetic metals (NMMs) [ 69 ] have been considered to tune magnetism behavior of 2D SiC. Among the two sites, C and Si, doping is found to be more favorable in Si-substituted sites, owing to the high structural stability of the resulting system [ 68 , 69 , 80 ].…”

“…Thus, not only the position of the dopant, but also its nature, affects the magnetic properties of the doped 2D SiC. Ferromagnetic behavior has also been reported for electrically doped SiC monolayer [ 76 ]. Further, magnetic coupling between the dopant and SiC is also very important.…”

“…This approach has been used successfully in manipulating magnetism and spin fluctuations in graphene. In 2D SiC, three types of vacancy defects have been studied; single C or Si vacancy, Si + C divacancy, and Si-C antisite defects in the monolayer [ 52 , 76 , 77 , 78 ].…”

“…Defects grown during the synthesis or surface defects may introduce some magnetism behavior into 2D SiC [ 76 , 78 ]. For instance, unpaired C vacancies could result in ferromagnetism behavior in monolayer SiC.…”