Stability and magnetic properties of SnSe monolayer doped by transition metal atom (Mn, Fe, and Co): a first-principles study

Abstract

Two dimensional (2D) tin selenium (SnSe) is an intriguing material with desired thermal and electric properties in nanoelectronics. In this paper, we carry on a density functional theory study on the stability and dilute magnetism of the 3d TM (Mn, Fe, and Co) doped 2D SnSe. Both the adsorption and substitution are in consideration here. We find that all the defects are electrically active and the cation substitutional doping (TM@Sn) is energetically favorable. The TM@Sn prefers to act as accepters and exhibits high-spin state with nonzero magnetic moment. The magnetic moment is mainly contributed by the spin-polarized charge density of the TM impurities. The magnetism is determined by the arrangement of the TM-3d orbitals, which is the result of the crystal field splitting and spin exchange splitting under specific symmetry. The magnetic and electronic properties of the TM@Sn are effectively modulated by external electric field (Eext) and charge doping. The Eext shifts the TM impurities relative to the SnSe host and then modifies the crystal field splitting. In particular, the magnetic moment is sensitive to the Eext in the Fe@Sn because the Eext induces distinct structure transformation. Based on the formation energy, doping electrons is a viable way to modulate the magnetic moment of TM@Sn. Doping electrons shift the 3d states towards low energy level, which induces the occupation of more 3d states and then the reduction of magnetism. These results render SnSe monolayer a promising 2D material for applications in future spintronics.

Recent Advances in SnSe Nanostructures beyond Thermoelectricity

“…In 2018, Yang et al [188] showed that the Cr/V-doped monolayer SnSe possessed an ferromagnetism (FM) ground state and could be a magnetic semiconductor with a band gap of 0.10 eV. Tang et al [189] revealed that the magnetism in cation substitutional TM doped 2D SnSe was determined by the arrangement of the TM-3d orbitals, and that the magnetic properties can be effectively modulated by the external electric field and charge doping. The magnetism in TM doped 2D SnSe was also reported by Luo et al [190] and Lu et al [191] The magnetic properties of TM doped monolayer β-SnSe [192] and δ-SnSe [193] have also been investigated.…”

First Principles Study of Gas Molecules Adsorption on Monolayered β-SnSe

“…In addition, due to the low cost, rich elements, and environmental friendliness, 2D IV-VI semiconductors have become a research hotspot in recent years. Monolayered SnSe is a fascinating 2D material due to its ideal electric and thermal properties in the field of nanoelectronics [20], which means it has promising applications in the photovoltaic industry, cut-off devices, and infrared lasers [21][22][23]. It has been reported that the adsorption behaviors of some small gas molecules on a GeS sheet [11], a SnS sheet [24], and an α-SnSe sheet [25].…”

Two-Dimensional SnSe Composited with One-Dimensional Mn Nanowires: A Promising Thermoelectric with Ultrahigh Power Factor

“…The lattice constants a and b are 4.41 and 4.28 Å, respectively, in good agreement with the data in the literature. 37,38,57,58 The monolayer SnSe possesses a hinge-like structure in the x−y plane, and the x and y directions are named as the armchair direction and zigzag direction, respectively, according to their geometric configurations. The 2D SnSe composited with Mn nanowires is termed as wMn− SnSe, where w denotes the number of armchair chains in each unit cell of the composite structures (Figure 1b presents the top and side views of 6Mn−SnSe with Mn nanowires along the zigzag direction).…”