Auger scattering in Landau-quantized graphene and Hg0.83Cd0.17Te

We explore the carrier dynamics in graphene and gapless bulk Hg0.83Cd0.17Te under Landau quantization. To this end, individual levels of the non-equidistant Landau ladders are pumped and probed by circularly polarized mid-infrared radiation pulses. While Auger scattering is very efficient in graphene, resulting in carrier redistribution on a ps timescale, this process is strongly suppressed in Hg0.83Cd0.17Te, yielding two orders of magnitude longer lifetimes.