SnP Monolayers: a New Type of Two-Dimensional Materials with High Stability, Carrier Mobility, and Magnetic Properties.

Searching for two-dimensional (2D) group V materials with ferromagnetism, elastic anisotropy, and carrier mobility and tunable band structure is one key to developing constantly developing nanodevices. The 2D monolayers SnP with x/y (1/1, 1/2, 1/3, and so on) coordination number are studied based on the particle-swarm optimization technique combined with the density functional theory optimization. Its thermal stability can be confirmed by molecular dynamics at 70K and 300K, indicating that the novel 2D materials have a stable existence. The electronic band structures of four stable structures suggest that all the monolayers of SnP are fully adjustable and flexible tunable band gaps semiconductors under the biaxial strain. The monolayer of P[Formula: see text]m-SnP with unique valence band structure can go from nonmagnetic to ferromagnetic by the hole doping because of the "Stoner criterion," and Pmc2-SnP is a direct-like gap semiconductor with in-plane elastic anisotropy to possess a high electron mobility as high as 800 cmV s along the k direction, which is much higher than that of MoS (∼ 200 cmV s). The optical absorption peak of the material is in the ultraviolet region. These discoveries expand the potential applications of the emerging field of 2D SnP structures in nanoelectronics.