Topological and Correlated States in Thin Films of Cadmium Arsenide

Bulk cadmium arsenide (Cd₃As₂) hosts topologically non-trivial bands in its electronic structure. In this talk, we will discuss topological and correlated phases in thin quantum wells of Cd₃As₂ that are tuned into a two-dimensional topological insulator state. We show that an in-plane Zeeman magnetic field induces a topological phase transition to a 2D Weyl semimetal phase, which shows a well-developed odd-integer quantum Hall effect under a small perpendicular magnetic field. We will discuss the evolution of the 2D Weyl semimetal phase as the film thickness is tuned. We will also report on our observations of a correlated insulator phase, which is characterized by the presence of pinned domains, analogous to a Wigner solid under finite disorder. We will discuss the unexpected breakdown of this phase under an applied magnetic field.