Detailed phase diagram of 3D nodal line semimetals with Γ5 random-mass (vector) disorder

Investigate the detailed phase diagram of three-dimensional nodal line semimetals subject to symmetry-breaking vector disorder of the form V(r) = (u0 + u(r)) Γ5, particularly in the vicinity of the transition line between insulating and metallic behavior, to characterize the phases and critical behavior in 3D and clarify how they compare to known 2D class-D and AII cases.

Background

The work shows that Γ5-type vector disorder can keep the system metallic for u0=0 and, when u0 ≠ 0 opens a clean gap, can drive a transition from an insulating to a metallic regime above a critical disorder strength.

They note analogies to 2D class-D superconductors and weak topological insulator surface states with random mass, but emphasize that details of the phase diagrams in those classes differ around the transition line. They explicitly leave the 3D nodal-line counterpart’s detailed phase diagram for future investigation.