Realization of unpinned two-dimensional dirac states in antimony atomic layers

Abstract

Two-dimensional (2D) Dirac states with linear dispersion have been observed in graphene and on the surface of topological insulators. 2D Dirac states discovered so far are exclusively pinned at high-symmetry points of the Brillouin zone, for example, surface Dirac states at $$\overline{{{\Gamma }}}$$ Γ ¯ in topological insulators Bi2Se(Te)3 and Dirac cones at K and $$K^{\prime}$$ K ′ points in graphene. The low-energy dispersion of those Dirac states are isotropic due to the constraints of crystal symmetries. In this work, we report the observation of novel 2D Dirac states in antimony atomic layers with phosphorene structure. The Dirac states in the antimony films are located at generic momentum points. This unpinned nature enables versatile ways such as lattice strains to control the locations of the Dirac points in momentum space. In addition, dispersions around the unpinned Dirac points are highly anisotropic due to the reduced symmetry of generic momentum points. The exotic properties of unpinned Dirac states make antimony atomic layers a new type of 2D Dirac semimetals that are distinct from graphene.

Unpinned Dirac-Fermions in Carbon–Phosphorus–Arsenic-Based Ternary Monolayers

“…The presence of buckling in the geometric structure of silicene plays a crucial role in the above process which leads to advantageous situation for silicene over graphene. , Moreover, silicon-based nanostructures are expected to be more compatible with industry as compared to carbon-based nanostructures. It is also noted that the DCs observed in graphene are exclusively pinned at highly symmetric K and K ′ points in BZ due to the presence of C 3 rotational symmetry in the planar honeycomb lattice . In the low-energy regime, the cones are also isotropic in momentum space.…”

Observation of 2D Weyl Fermion States in Epitaxial Bismuthene

“…The first step is to find a 2D Dirac material with a narrow SOC gap such as silicene, antimonene, and bismuthene (Fig. 1ci) [40,[52][53][54][55][56]. After a suitable material is found, a perturbation is then applied to break space-inversion symmetry (Fig.…”

Manipulating Dirac States in BaNiS2 by Surface Charge Doping

“…New perspectives have been disclosed by the discovery of materials with unpinned Dirac cones, such as the surface of ZrSnTe, atomic layers, e.g. Sb, transition-metal dichalcogenides, and nonsymmorphic layered compounds, such as ZrSiS and BaNiS 2 …”

“…New perspectives have been disclosed by the discovery of materials with unpinned Dirac cones, such as the surface of ZrSnTe, 2 atomic layers, e.g. Sb, 3 transition-metal dichalcogenides, 4 and nonsymmorphic layered compounds, such as ZrSiS 5 and BaNiS 2 . 6 In this letter, we consider BaNiS 2 , a prototype of correlated Dirac semimetal where the Dirac states are located along the Γ−M symmetry line.…”