Primordial black holes from string inflation

We present a single-field string inflationary model which allows for the generation of primordial black holes in the low mass region where they can account for a significant fraction of the dark matter abundance. The potential is typical of type IIB fibre inflation models and features a plateau at CMB scales and a near inflection point at small distance scales where the power spectrum is enhanced due to a period of ultra slow-roll. The tunability of the underlying parameters may be guaranteed by scanning through the string landscape and their stability against quantum corrections is ensured by an effective shift symmetry.