Synthesis and characterization of Cd₃As₂ heterostructures as a route to broken time reversal symmetry in a Dirac semimetal

Thin films of Cd₃As₂ have attracted significant interest in recent years for studying the effects of quantum confinement and strain on a canonical Dirac semimetal. Such epitaxially grown thin films also provide an opportunity to explore proximity effects that break time-reversal symmetry. Magnetically-doped III-V semiconductors are attractive in this context because they serve as excellent ferromagnetic substrates for the growth by molecular beam epitaxy (MBE) of Cd₃As₂ films of reasonable interfacial, structural, and electronic quality. To this end, we report on the MBE growth of Cd₃As₂ thin films on (In,Mn)As (001) which is a well-established ferromagnetic semiconductor with perpendicular magnetic anisotropy. A key challenge is to engineer heterostructures with sharp interfaces and with electrical transport dominated by the Cd₃As₂ layer. We characterize the structural characteristics of these heterostructures using x-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy. We also use Hall effect measurements to search for evidence of proximity-induced magnetism in the Cd₃As₂ layer. Finally, we will report on measurements of angle-resolved photoemission spectroscopy above and below the Curie temperature of the (In,Mn)As layer.