Electronic, elastic and lattice dynamic properties of the topological Dirac semimetal Na3Bi

Abstract

Na3Bi is a topological Dirac semimetal, which has a three-dimensional topological Dirac node at its Brillouin zone center. Here we performed a systematic study on its electronic, elastic and lattice dynamic properties by first principles calculation to enrich our knowledge on it. Studies confirmed the semimetallic nature of Na3Bi. Calculated elastic properties indicate that Na3Bi is mechanically stable but anistropic. Na3Bi is a brittle crystal. Shear deformation is easier to occur in its (00 ± 1)[0 ± 10] slip system. The infrared- and Raman-active modes at its Brillouin zone center were identified and detailedly discussed. All the computed vibrational frequencies of the phonons are positive, indicating the dynamical stability of Na3Bi. The Born effective charges and dielectric constants of Na3Bi were also calculated.