SUPERFLUIDITY NEAR SOLID-SURFACES IN A THOMAS-FERMI-DIRAC JELLIUM MODEL - POTASSIUM AND NICKEL

Generally an almost ideal Fermi system with attraction between fermion s possesses non-Newtonian behavior. Electrons described according to t he Thomas-Fermi-Dirac model (TFD) form such a system. We investigated these electrons in solids with surfaces. In this kind of non-Newtonian motions, superfluidity appeared under certain condition. This conclus ion is shown theoretically when we apply this model to potassium and n ickel. For K, there is a layer of thickness only 0.33 bohr near the su rface in which electrons move to higher potential locations similar to the climbing effect under gravity although non-Newtonian motions occu r throughout the system. For nonmagnetic 4s(2) electrons of Ni, there may also be a layer of this kind of thickness 0.25 bohr near the surfa ce after we choose the surface density properly in theory. In all thes e systems, electrons are reflected from surface to interior layers.