  We study ground state properties and particle excitation spectra across a
commensurate charge density wave transition in a system of strongly interacting
fermions, using series expansion methods and mean-field theory. We consider a
1/3-filled system of spinless fermions on a triangular-lattice, with hopping
parameter $t$, nearest-neighbor repulsion $V$, and a sublattice dependent
chemical potential $\mu_s$. The phase transition is found to be first order for
$\mu_s=0$, but becomes continuous with increasing $\mu_s$. The particle and
hole excitation spectra exhibit dramatic changes in the vicinity of the phase
transitions and in the charge-density wave ordered phase. We discuss the
relevance of this study to the Pinball Fermi liquid phase postulated
theoretically in earlier studies as well as to various strongly correlated
triangular-lattice materials.
