Tetragonal Mexican-Hat Dispersion and Switchable Half-Metal State with Multiple Anisotropic Weyl Fermions in Penta-Graphene

Abstract

In past decades, the ever-expanding library of 2D carbon allotropes has yielded a broad range of exotic properties for the future carbon-based electronics. However, the known allotropes are all intrinsic nonmagnetic due to the paired valence electrons configuration. Based on the reported 2D carbon structure database and first-principles calculations, herein we demonstrate that inherent ferromagnetism can be obtained in the prominent allotrope, penta-graphene, which has an unique Mexican-hat valence band edge, giving rise to van Hove singularities and electronic instability. Induced by modest hole-doping, being achievable in electrolyte gate, the semiconducting pentagraphene can transform into different ferromagnetic half-metals with room temperature stability and switchable spin directions. In particular, multiple anisotropic Weyl states, including type-I and type-II Weyl cones and hybrid quasi Weyl nodal loop, can be found in a sizable energy window of spin-down half-metal under proper strains. These findings not only identify a promising carbon allotrope to obtain the inherent magnetism for carbon-based spintronic devices, but highlight the possibility to realize different Weyl states by combining the electronic and mechanical means as well.

References in corpus (26)

• Electric Field Effect in Atomically Thin Carbon Films
• Half-Metallic Graphene Nanoribbons
• Type-II Weyl Semimetals
• Controlling electron-phonon interactions in graphene at ultra high carrier densities
• Topological nodal line semimetals
• Magnetic Correlations at Graphene Edges
• T-Carbon: A Novel Carbon Allotrope
• Controlling many-body states by the electric-field effect in a two-dimensional material
• Tunable Magnetism and Half-Metallicity in Hole-doped Monolayer GaSe
• Topological Semimetals Predicted from First-principles Calculations
• Irvsp: to obtain irreducible representations of electronic states in the VASP
• Spin-orbit-free Weyl-loop and Weyl-point semimetals in a stable three-dimensional carbon allotrope
• Accessing the transport properties of graphene and its multi-layers at high carrier density
• Double crystallographic groups and their representations on the Bilbao Crystallographic Server
• Multiferroic Two-Dimensional Materials
• Band Structure and Optical Transitions in Atomic Layers of Hexagonal Gallium Chalcogenides
• Magnetism of Substitutional Co Impurities in Graphene: Realization of Single $\pi$-Vacancies
• Mexican Hat and Rashba Bands in Few-Layer van der Waals Materials
• Liganded Xene as a Prototype of Two-Dimensional Stiefel-Whitney Insulators
• Magnetic frustration in an iron based Cairo pentagonal lattice
• Hybrid Nodal Loop Metal: Unconventional Magnetoresponse and Material Realization
• Discovery of Weyl nodal lines in a single-layer ferromagnet
• Two-dimensional Weyl nodal line semimetal in high Curie temperature d0 ferromagnet K2N monolayer
• Topological carbon materials: a new perspective
• Slow Spin Relaxation in Single Endohedral Fullerene Molecules
• Band-edge superconductivity

Cited by in corpus (1)

• Existence of Mexican-hat dispersion and symmetry group of a layer