  We report first principles theory-based comparative electronic transport
studies performed for an atomic chain of Au, bare Cd9Te9 cage-like cluster and
single transition metal (TM) (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd)
atom encapsulated within the Cd9Te9 using Au(111) as electrodes. The bare
cluster is semiconducting and acts as a tunnel barrier up to a particular
applied bias and beyond that, the device has a linear current-voltage
relationship. Several TM (Ti, V, Cr, Mn, Fe) encapsulated in the cage show
half-metallic behavior and spin filtering effect in the I-V characteristics of
the device. A detailed qualitative and quantitative analysis of I-V
characteristics for metallic, semiconducting, and half-metallic nanostructures
has been carried out.
