Electronic transport properties of nanostructured metals could
be evidently influenced by their characteristic lengths. Fujita
et al. [144] investigated the conductivity of np-Au at low temperatures
and strong magnetic fields. With the characteristic nanopore
sizes down to 14 nm, np-Au still exhibits metal-like
behavior with very low resistance, which is well explained by
Landau Fermi liquid theory with the mean free paths identical to
the average nanopore sizes. It also shows extremely low magnetoresistance
in strong magnetic field (Fig. 13) [144]. Generally, metal
magnetoresistance increases at lower temperature owing to the
reduction of thermal phonon scattering. However, the np-Au
sample with a pore size of 14 nm shows very weak temperature
dependence. This anomalous temperature dependence should be
attributed to the disordered gold ligaments restraining the electron
cyclotron motion in strong magnetic fields. This study indicates the
manipulation of electron transport by tailoring the 3D nanostructures
of np-Au.