The integration of ferromagnetic and semiconducting properties in a single two-dimensional (2D) material has been recognized as a fertile ground for fundamental science as well as for practical applications in information processing and storage. CrI 3 monolayer has recently drawn much attention due to its 2D long-range ferromagnetic (FM) order. However, its Curie temperature (T C ) is too low (∼45 K) for practical spintronic applications. Here, we show that the in-plane FM coupling of CrI 3 can be remarkably enhanced by constructing a 2D heterostructure where CrI 3 monolayer is supported on a nonmagnetic normal semiconductor/insulator substrate. Choosing MoTe 2 monolayer as a substrate, we find that the CrI 3 /MoTe 2 2D heterostructure is an intrinsic semiconducting ferromagnet with T C of ∼60 K. The T C can be further increased to ∼85 K by applying an out-of-plane pressure of ∼4.2 GPa. The doubling of the T C in this 2D heterostructure comes from the introduction of extra spin superexchange (Cr−Te−Cr) paths. Our findings provide a promising pathway to improve ferromagnetism in 2D semiconductors, which can stimulate further theoretical and experimental interest.

Two-dimensional (2D) ferromagnetic (FM) semiconductors with a direct electric band gap have recently drawn much attention due to their promising potential for spintronic and magneto-optical applications.

Two-dimensional (2D) transition metal dinitrides (TMN2) have attracted increasing attention owing to their diverse geometry configurations and versatile properties. Because of the large electrostatic repulsion between highly charged N3- ions,...

Atomically thin hexagonal boron nitride (h-BN) layers have been used as an ultra-thin spacer layer for metal-insulator-metal (MIM) structures, which enables a wide range of applications such as nanocapacitors and field-effect tunneling transistors. Although pristine h-BN layers, produced by chemical vapor deposition (CVD) methods, are always with ubiquitous grain boundaries (GBs), the contact of such layers with transition metal (TM) has not been explored. Here, we studied h-BN monolayer with GBs on Ni(111) and Cu(111) surfaces through a comprehensively first-principles calculation. Our results show that for the free-standing h-BN monolayer with GBs, it presents a moiré pattern characteristic and its energy gap is narrowed by about 38%. When h-BN with GBs is deposited onNi(111) and Cu(111) surfaces, the GBs containing B-B pairs are attracted to the TM surface while the GBs with N-N pairs(GBs-N) parts are repelled from the surfaces. Interestingly, the calculated Schottky barriers (SBs) for electrons between the h-BN layer and the TM surfaces almost disappear due to the existence of GB structures. Thus, our results predicted that h-BN with GBs may form ohmic contact with TM surfaces, which can be used in real electric devices.