Monte Carlo study of the statistics of electron capture by shallow donors in silicon at low temperatures

Detection and Modeling of Hole Capture by Single Point Defects under Variable Electric Fields

Understanding carrier trapping in solids has proven key to semiconductor technologies, but observations thus far have relied on ensembles of point defects, where the impact of neighboring traps or carrier screening is often important. Here, we investigate the capture of photogenerated holes by an individual negatively charged nitrogen-vacancy (NV) center in diamond at room temperature. Using an externally gated potential to minimize space-charge effects, we find the capture probability under electric fields of variable sign and amplitude shows an asymmetric-bell-shaped response with maximum at zero voltage. To interpret these observations, we run semiclassical Monte Carlo simulations modeling carrier trapping through a cascade process of phonon emission and obtain electric-field-dependent capture probabilities in good agreement with experiment. Because the mechanisms at play are insensitive to the characteristics of the trap, we anticipate the capture cross sections we observe─largely exceeding those derived from ensemble measurements─may also be present in materials platforms other than diamond.

Unconventional Bloch-Grüneisen Scattering in Hybrid Bose-Fermi Systems

We report on the novel mechanism of electron scattering in hybrid Bose-Fermi systems consisting of a two-dimensional electron gas in the vicinity of an exciton condensate: We show that in certain ranges of temperatures, the bogolon-pair-mediated scattering proves to be dominating over the conventional acoustic phonon channel, over the single-bogolon scattering, and over the scattering on impurities. We develop a microscopic theory of this effect, focusing on GaAs and MoS_{2} materials, and we find the principal temperature dependence of resistivity, distinct from the conventional phonon-mediated processes. Further, we scrutinize parameters and suggest a way to design composite samples with predefined electron mobilities, and we propose a mechanism of electron pairing for superconductivity.