Ion Mixing Processes

Abstract

ABSTRACTWe consider ion mixing in the low temperature regime, where it is insensitive to temperature. Mixing of most thin markers is Gaussian, independent of irradiation flux, and varies linearly with fluence. However, the mixing in some media varies widely between markers of similar mass and appears to correlate with thermal diffusion constants. In bilayer systems, the profile of long-range mixing is exponential, and the number of mixed atoms scales linearly with fluence. This can be modeled successfully with simple collisional theory. Short range mixing scales with the square root of the fluence, but again shows strong correlations with known bulk chemical properties. We conclude that chemical driving forces and low energy transport mechanisms such as interstitial migration play major roles in ion mixing, even at low temperatures.