Abstract
We predict from density functional theory based electronic structure calculations that a monolayer made up of carbon and arsenic atoms with a chemical composition forms an energetically and dynamically stable system in two geometrical arrangements, namely, buckled and puckered configurations. The results of electronic structure calculations predict that the puckered monolayer is a metal, whereas the buckled monolayer is a semimetal. Interestingly, the electronic band structure of the buckled configuration possesses a linear dispersion and a Dirac cone at the Fermi level around the high-symmety point in the reciprocal lattice. Thus, at low-energy excitation (up to 105 meV), the charge carriers in this system behave as massless Dirac fermions. Detailed analysis of partial density of state indicates that the orbital of C atoms contributes significantly to the states which form the linear dispersion and hence the Dirac cone around the Fermi level. This suggests the existence of a strong correlation between the linear dispersion (Dirac cone) and -like hybridization of the orbitals of C atom. Thus the electronic properties of monolayer are similar to those of graphene and other group-IV based monolayers like, silicene and germanene. In addition, we have also investigated the influence of mechanical strain on the properties of monolayer. Our results indicate that the monolayer possesses linear dispersion in the electronic band structure for a wide range of mechanical strain from % to 20%, though the position of Dirac point may not lie exactly at the Fermi level. Finally, we wish to point out that monolayer belongs to the class of Dirac materials where the behavior of particles, at low-energy excitations, is characterized by the Dirac-like Hamiltonian rather than the Schrodinger Hamiltonian.
1 More- Received 3 April 2019
- Revised 1 September 2019
DOI:https://doi.org/10.1103/PhysRevB.100.205404
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