SUPER STRONG EFFECT OF SURFACE IMPURITIES ON THE RESISTANCE AND HALL-EFFECT OF QUENCH CONDENSED CS FILMS

Thin films of Cs, quench condensed onto a He cold quartz plate, posses s electronic mean free paths which considerably exceed the film thickn esses. When theses films are covered in situ with sub monolayers of Au , Ag, In, Rh and Pb in the range between 0.01 and 1 monolayers the fil m resistance and the Hall constant increase dramatically. This corresp onds to a scattering cross section of the surface impurities which is larger than 1 in units of 4 pi/k(F)(2). Various models are explored to explain these unusual behavior. None yields a satisfactory explanatio n for this extremely strong effect of surface impurities on the resist ance and the Hall effect.