First-Principles Prediction of Room-Temperature Ferromagnetic Semiconductor MnS₂ via Isovalent Alloying

Abstract

Although semiconducting ferromagnetism has been experimentally discovered in two-dimensional (2D) crystals, the spin coupling is still quite weak, which leads to a rather low Curie temperature (T C ). Thus, it is quite confused whether the ferromagnetism in semiconductors can survive under room temperature. Here, through isovalent alloying, we propose that the semiconducting ferromagnetism of 2D MnS 2 can be significantly enhanced with T C improved higher than room temperature. Based on first-principles calculations, we systematically studied the properties of original MnS 2 and the isovalent alloying systems Mn x Re 1−x S 2 . The spin coupling is significantly enhanced by introducing Mn−Re virtual bonds, and the highest T C of the system reaches 360 K. Besides this, a tensile strain will further enhance the ferromagnetic couplings as well as the uniaxial magnetic anisotropy, which is important for the stabilization of longrange ferromagnetic order in a 2D system. Our results not only broaden the family of 2D ferromagnetic semiconductors but also provide the direct clues to prepare such hightemperature magnetic materials for promising applications in spintronics.

Electronic and Magnetic Properties of a Two-Dimensional Transition Metal Phosphorous Chalcogenide TMPS4

“…Two-dimensional (2D) materials have garnered tremendous interests since the discovery of graphene along with its superior electronic properties. , In recent years, 2D materials beyond graphene have been successfully exfoliated or synthesized, such as insulator hexagonal BN, semiconductor MoS 2 and black phosphorous (BP), − magnetic semiconductor CrI 3 , and Cr 2 Ge 2 Te 6 . , These new materials have greatly expanded the family of 2D materials and promised various electronic and spintronic applications. − In particular, the discovery of single-layer MoS 2 has further promoted the realization of a broad range of 2D transition metal dichalcogenides (TMDs), such as WS 2 , MoSe 2 , WSe 2 , WTe 2 , etc. Their similar crystal structure and similar synthesis process enable the construction of 2D multinary TMDs, including alloyed TMD nanosheets and lateral TMD heterostructures, − which further tune their properties and optimize the performance for specific applications. In this regard, discovering families of isomorphic 2D materials with different properties can provide much broader applications.…”

Boosting the Curie Temperature of Two-Dimensional Semiconducting CrI3 Monolayer through van der Waals Heterostructures

“…These materials have a unique potential for new physical phenomena, because magnetism occurs spontaneously without the need to introduce magnetic dopants, as done in conventional magnetic semiconductors. − As a result, a perfect crystalline order is preserved. The above discoveries have motivated a great deal of interest in related 2D ferromagnetic materials (e.g., Fe 3 GeTe 2 , CrOCl, and CrWI 6 ). − Unlike 2D FM metals, which show a very high T C even up to room temperature (e.g., VSe 2 and MnSe 2 ), the T C of CrI 3 FM semiconductor is only ∼45 K, which hinders its potential for practical applications. Therefore, many works have been devoted to improving T C of 2D ferromagnetic materials. − …”

Modulating superexchange strength to achieve robust ferromagnetic couplings in two-dimensional semiconductors

“…Where <ij> and << ij>> represent the first and second nearest couplings, which is generally sufficient to describe the exchange couplings in magnetic monolayers. [39] [40] The calculated exchange parameters as J1 and J2 are listed in Table 1. Generally, this series exhibit ferromagnetic J1 ~ 30 meV, and it is almost ten times of the value for…”