Magnetic quantum criticality: The role of the Fermi surface geometry

Abstract

We investigate magnetic quantum phase-transitions in bulk correlated metals. To this end, we focus on the Hubbard model on different cubic lattices as a function of temperature and electronic density, determining the relevant regimes around its quantum magnetic transition, i.e. classical, quantum critical, and quantum disordered, as well as the corresponding (thermal/non-thermal) quantum critical exponents. Our numerical results, based on dynamical mean-field theory, together with supporting analytical derivations, rigorously demonstrate how and why the presence of different kinds of Kohn anomalies on the underlying Fermi surface (i) drives the quantum critical behavior above the quantum critical point and (ii) shapes the whole phase diagram around it. Our findings highlight the importance of an explicit inclusion of such Fermi surface geometrical properties into the universality class definition for magnetic quantum phase-transitions in correlated metals.

8 pages (including references) + 2 pages of (newly added) End Matter section, 4 figures