Breakdown of Landau Fermi liquid properties in the 2D Boson-Fermion model

Abstract We study the normal state spectral properties of the fermionic excitations in the Boson-Fermion model. The fermionic single particle excitations show a flattening of the dispersion as the Fermi vector kF is approached from below, forshadowing a Bogoliubov spectrum of a superconducting ground state. The width of the quasiparticle excitations near kF increases monotonically as the temperature is lowered. In the fermionic distribution function this temperature dependence is manifest in a strong modification of n( k ) in a small region below kF, but a nearly T independent n( k F ) .