Emergence of Dirac cone in CsPbBr3 perovskite-based two-dimensional photonic crystals

Abstract

In this paper, it has been proposed that all-inorganic perovskite materials can be used to design and fabricate two-dimensional (2D) photonic crystals. The theoretical study performed here shows that these perovskite-based 2D photonic crystals exhibit a Dirac cone dispersion. In this study, cesium lead bromide (CsPbBr3) having rectangular shapes of varying widths (50, 100, and 150 nm) and a fixed height of 300 nm are arranged in a regular manner with a lattice constant of 500 nm. The pattern of these photonic crystals exhibits C4v symmetry. It has been observed when these perovskite materials, arranged in a rectangular shape, are having a certain dimension; they display a Dirac cone dispersion at the centre of the Brillouin zone at a frequency close to peta-hertz. Further, these photonic crystals are used to manipulate the propagation of electromagnetic (EM) waves of frequency ∼4 × 1014 Hz. Near this frequency, the photonic crystals respond as a nearly zero refractive index material, which allows passing EM waves even in presence of an obstacle. This study can be expanded to design and fabricate two-dimensional photonic crystals based on various perovskite materials.