Mean free path reduction conduction electron

The high density of states found in the 3c/bands of Fe, Co, and Ni leads to a reduction of the mean free path of the electrons in this band. This causes a decrease in their mobility and hence in the electrical conductivity of these elements compared to simple metals and copper where the conduction electrons are in s/p bands. 

One can imagine from these experimental results that PDA chains inside poly(DCHD)shell may contact with some points on the surface of Ag core [47,49]. These contact points at hetero nano-interface might be anchors to disturb and depress the plasma oscillation, and then diminish the mean-free-path of conduction free electrons in VB of Ag core. In other words, the LSP of Ag core would damp simply without changing the resonance frequency, owing to the reduction of electronic conductive domain induced by locally and strongly physicochemical interaction at the core/shell interface in the hybridized NCs [103,105]. 

Since the mean free path A is already quite short in the dense metal, the conclusion seems unavoidable that the loffe-Regel limit of the NFE regime is reached around 11 g cm so that A a and, moreover, that the Edwards cancellation theorem begins to fail. Thereafter, with further reduction of the density to about 9 g cm , the conductivity drops by another order of magnitude and the Hall coefficient increases sharply to about three times the free electron value. 

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