Quasiparticle effective mass divergence in two dimensional electron systems

Within the infinite series of ring (or bubble) diagram approximation for the electronic self-energy as appropriate for the long-range Coulomb interaction, we calculate the density-dependent T=0 Fermi liquid quasiparticle effective mass renormalization in two dimensional (2D) electron systems in the random-phase-approximation (RPA). We find that the quasiparticle effective mass increases very strongly with increasing $r_s$, exhibiting an unexpected divergence at a critical $r_s$ value ($\sim 16$ in the ideal 2D system). We discuss the possibility for and the consequences of such an interaction induced effective mass divergence as the electron density decreases, and critically comment on the likely theoretical scenarios which could lead to such a low density effective mass divergence in electron liquids.