Cd3As2

Cd3As2, also known as cadmium arsenide, is an inorganic binary compound consisting of cadmium and arsenic. Since the mid-2010s, it has been studied as a three-dimensional Dirac semimetal, in which conduction and valence bands touch at discrete Dirac nodes and dispersions are approximately linear in all three momentum directions near those points.

Crystal structure: Cd3As2 crystallizes in a tetragonal lattice and typically forms as single crystals or ingots. The crystal symmetry protects Dirac nodes along the kz axis; breaking inversion or time-reversal symmetry or perturbations like strain or doping can split a Dirac node into Weyl nodes or open a gap, enabling transitions to other topological phases.

Electronic properties: The linear dispersion near the Dirac points yields high carrier mobility and low effective mass; Cd3As2 shows high room-temperature mobility and large magnetoresistance in experiments. Studies using angle-resolved photoemission spectroscopy (ARPES) and transport measurements have mapped its Dirac points and tested predictions of relativistic-like fermions in solids.

Synthesis and forms: Cd3As2 can be grown as single crystals by methods such as chemical vapor transport or cadmium-rich flux growth; it is also studied in thin-film and nanostructure forms for device integration.

Applications and significance: As a model system for three-dimensional Dirac and Weyl semimetal physics, Cd3As2 serves as a platform for exploring relativistic-like quasiparticles, topological phase transitions, and potential electronic and spintronic devices.

Environmental and safety considerations: Cadmium and arsenic are toxic; handling requires appropriate safety protocols.