Impurity heterogeneity in natural pyrite and its relation to internal electric fields mapped using remote laser beam induced current

Regions of band-bending in naturally occurring semiconducting sulfides are thought to drive electrochemical reactions with passing fluids. Metal bearing fluids within the right pH range interact with the electric fields at the surface resulting in precious metal ore genesis, even in under-saturated solutions. Metal reduction at the surface occurs via field assisted electron transfer from the semiconductor bulk to the ion in solution via surface states. Better understanding the role these regions and their texturing play on nucleating ore growth requires imaging of electric field distributions near the sulfide surface and correlation with underlying elemental heterogeneity. In this paper we discuss PIXE measurements made on the CSIRO Nuclear Microprobe and correlate elemental maps with laser beam induced current maps of the electric field distribution.