Sommerfeld enhancement factor in two-dimensional Dirac materials

In this work the above-band gap absorption spectrum in two-dimensional Dirac materials is calculated with account for interaction between photocarriers. Both screened Rytova-Keldysh and pure Coulomb attraction potentials electron hole are used study. We find that, under consideration, enhances absorbance narrow interband edge region, a sharp contrast to band model parabolic free-carrier energy dispersion. develop an approximation of weak which allows us reproduce main features exactly Sommerfeld factor. show substantial reduction factor at higher frequencies due single-particle renormalization.