Abstract

The self-consistent Born approximation quantitatively fails to capture
disorder effects in semimetals. We present an alternative, simple-to-use
non-perturbative approach to calculate the disorder induced self-energy.
It requires a sufficient broadening of the quasiparticle pole and
the solution of a differential equation on the imaginary frequency
axis. We demonstrate the performance of our method for various paradigmatic
semimetal Hamiltonians and compare our results to exact numerical
reference data. For intermediate and strong disorder, our approach
yields quantitatively correct momentum resolved results. It is thus
complementary to existing RG treatments of weak disorder in semimetals.