Trends in hot carrier distribution for disordered noble-transition metal alloys

We developed and tested an approach for predicting trends for efficient hot carrier generation among disordered metal alloys. We provide a simple argument for the importance of indirect transitions in the presence of disorder, thus justifying the use of joint density of states (JDOS)-like quantities for exploring these trends. We introduce a newJDOS-like quantity,JDOS_K, which heuristically accounts for longer lifetimes of quasiparticles close to the Fermi energy. To demonstrate the efficacy of this new quantity, we apply it to the study of Cu₅₀X₅₀where X = Ag, Au, Pd and Y₅₀Pd₅₀where Y = Au, Ni. We predict that Ni₅₀Pd₅₀produces the most hot carriers among the alloys considered. The improvement in the density of excited photocarriers over the base alloy used, Cu₅₀Ag₅₀, is 3.4 times for 800 nm and 19 times for 1550 nm light. This boost in hot-carrier generation is consequence of the ferromagnetic nature of the Ni alloy. We argue that our method allows efficient material-specific predictions for low bias photoconductivity of alloys.