Nodal Arc in Disordered Dirac Fermions: Connection to Non-Hermitian Band Theory

Understand

We show that Dirac fermion systems in two dimensions generally exhibit disorder-induced nodal arc replacing the nodal point and tilted Dirac cone, provided that the two components of the Dirac fermion correspond to two distinct orbitals unrelated by symmetry.

• This result is explicitly demonstrated using renormalization group analysis in a disordered Dirac model that we introduce, where the disorder potential acts differently on the two orbitals.
• As we show by numerical simulations and self-consistent Born approximation calculation, this drives the system into a new strongly disordered phase.