Optimization of Molecular Beam Epitaxial Growth of thin films of a three-dimensional Dirac semimetal

Three dimensional topological Dirac semimetals (TDS) such as Na3Bi, have attracted great attention in condensed matter physics due to their rich physics and possible revolutionary technological applications. Confining Na3Bi to the ultrathin regime opens a bulk bandgap and has shown to exhibit the quantum spin Hall effect. We will show our results on the high quality epitaxial thin film growth of Na3Bi on a magnetic insulator using molecular beam epitaxy (MBE) technique. We will discuss and compare our result on the epitaxial growth of Na3Bi using two different growth techniques, i.e., flux matched co-deposition and alternating layer by layer growth. The high-quality crystallinity of the Na3Bi films is monitored using in-situ reflection high energy electron diffraction (RHEED). The MBE grown films are further characterized (charge carrier density and charge carrier mobility) via in-situ magnetotransport measurements in an ultra-high vacuum environment.