Appearance of Fermion Condensation Quantum Phase Transition in Different Fermi Liquids

Abstract

We show that the quasiparticle effective mass $M^*$ diverges as a function of the system's density $x$, $M^*\propto 1/(x-x_{FC})$, when a system approaches the critical point $x_{FC}$ at which the fermion condensation quantum phase transition (FCQPT) occurs. Such behavior is of general form and takes place in both three dimensional systems and two dimensional ones. We demonstrate that a system which has undergone FCQPT and lies close to the critical point $x_{FC}$ can be driven back into the normal Fermi liquid by applying a small magnetic field $B$. As the field $B$ is reduced, the system is tuned back to the critical point and the effective mass diverges as $M^*\propto 1/\sqrt{B-B_{FC}}$ where $B_{FC}$ is the maximum field at which FCQPT takes place. We demonstrate the constancy of the Kadowaki-Woods ratio when approaching the critical point at the fields $B>B_{FC}$. Analyzing recent experimental data on the effective mass behavior in a strongly correlated two dimensional fluid $^3$He, in metallic two dimensional electron systems and in heavy-fermion systems, we show that the observed behavior is in agreement with our consideration. As a result, we may conclude that FCQPT can be conceived of as a universal cause of the strongly correlated regime in different Fermi liquids.