Photoemission and transport studies of the metal-insulator transition in granular palladium films

Photoemission and resistivity measurements of granular Pd samples are reported which exhibit a metal-insulator transition with decreasing metal fraction. As the net metallic concentration is reduced the resistivity passes through √T , lnT, exp]+(A/T)/sup 1/4/], and insulating exp]+B/T)/sup 1/2/] temperature dependences while the photoemission results show a continuous reduction in the Pd local density of states within 1 eV of the Fermi level. In the insulating regime a gap is observed in the photoemission spectrum