Non metal-metal transition in Bruggeman optical theory for inhomogeneous media

2014 The Bruggeman optical effective medium theory of the dielectric permeability 03B5e(03C9) of inhomogeneous media is analysed for metal-dielectric compounds in relation to the non metal-metal transition. The influence of the constituent-material parameters (free-electron parameters and bound-state polarization) on both the real and imaginary parts of 03B5e(03C9) is investigated in detail for the full range of metal filling factors and for optical to farinfrared wavelengths. A physical interpretation is formulated in terms of bound-state polarization, interfacial polarization and Drude conduction-electrons contributions. The results thus obtained are eventually compared to those of other effective medium theories : Maxwell Garnett modified by Cohen et al., Ping Sheng. J. Physique 45 (1984) 623-631 MARS 1984,