INTERACTING FERMIONS - COEXISTENCE OF LOCAL AND BOUND FERMION PAIRS AND BREAKDOWN OF FERMI-LIQUID BEHAVIOR

Various Fermionic models with realistic screened interaction in differ ent spatial dimensions are studied in the low energy limit by scaling energies. It is found that there exist possibilities for a departure f rom Fermi Liquid (FL) behavior in two dimensions, In particular for a two-dimensional electron gas with bare interaction of logarithmic form , the breakdown of FL behavior occurs unconditionally. Detailed analys is of these models in two-dimension shows the possibilities for presen ce of correlated local Fermion pairs and bound Fermion pairs even in t he normal phase.