Ferromagnetism with in-plane magnetization, Dirac spin-gapless semiconducting property, and tunable topological states in two-dimensional rare-earth-metal dinitrides

Abstract

As the bulk single-crystal MoN2/ReN2 with a layered structure was successfully synthesized in experiment, transition-metal dinitrides have attracted considerable attention in recent years. Here, we focus on rare-earth-metal (Rem) elements and propose seven stable Rem dinitride monolayers with a 1T structure, namely 1T-RemN2. These monolayers have a ferromagnetic ground state with in-plane magnetization. Without spin-orbit coupling (SOC) effect, the band structures are spin-polarized with Dirac points at the Fermi level. Remarkably, the 1T-LuN2 monolayer shows an isotropic magnetic anisotropy energy in the xy-plane with in-plane magnetization, indicating easy tunability of the magnetization direction. When rotating the magnetization vector in the xy-plane, our proposed model can accurately describe the variety of the SOC band gap and two topological states (Weyl-like semimetal and Chern insulator states) appear with tunable properties. The Weyl-like semimetal state is a critical point between the two Chern insulator states with opposite sign of the Chern numbers. The large nontrivial band gap (up to 60.3 meV) and the Weyl-like semimetal state are promising for applications in spintronic devices.

27 pages, 6 figures

References in corpus (15)

• Electric Field Effect in Atomically Thin Carbon Films
• Two Dimensional Atomic Crystals
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Gate-tunable Phase Transitions in 1T-TaS${}_2$
• Z2Pack: Numerical Implementation of Hybrid Wannier Centers for Identifying Topological Materials
• Strain-induced Isostructural and Magnetic Phase Transitions in Monolayer MoN${}_2$
• Dirac spin gapless semiconductors: Ideal platforms for massless and dissipationless spintronics and new (quantum) anomalous spin Hall effects
• Ferromagnetic hybrid nodal loop and switchable type-I and type-II Weyl fermions in two-dimension
• Magnetism and Magneto-optical Effects in Bulk and Few-layer CrI${}_3$: A Theoretical GGA + U Study
• Spin gapless semiconductors
• Two-dimensional topological semimetals
• In-Plane Magnetization Induced Quantum Anomalous Hall Effect in Atomic Crystals of Group-V Elements
• Fully spin-polarized nodal loop semimetals in alkaline-metal monochalcogenide monolayers
• Weyl-like points from band inversions of spin-polarised surface states in NbGeSb
• Discovery of Ĉ${}_2$ rotation anomaly in topological crystalline insulator SrPb