Electronic and magneto-optical properties of monolayer phosphorene quantum dots

We theoretically investigate the electronic and magneto-optical properties of rectangular, hexangular, and triangular monolayer phosphorene quantum dots (MPQDs) utilizing the tight-binding method. The electronic states, density of states, electronic density distribution, and Laudau levels as well as the optical absorption spectrum are calculated numerically. Our calculations show that: (1) edge states appear in the band gap in all kinds of MPQDs regardless of their shapes and edge configurations due to the anisotropic electron hopping in monolayer phosphorene (MLP). The charge density of any edge state is only localized in specific edges of a MPQD, which is distinct from that in graphene quantum dots; (2) the magnetic levels of MPQDs exhibit a Hofstadter-butterfly spectrum and approach the Landau levels of MLP as the magnetic field increases. A 'flat band' appears in the magneto-energy spectrum which is totally different from that of MLP; (3) the electronic and optical properties can be tuned by the dot size, the types of boundary edges and the external magnetic field.