Spin-density waves and the superconductivity dome in heavy electron systems with nested Fermi surfaces

Abstract

The nesting of the Fermi surfaces of an electron and a hole pocket separated by a nesting vector $\mathbf{Q}$ and the interaction between electrons give rise to itinerant antiferromagnetism. The order can gradually be suppressed by mismatching the nesting and a quantum critical point is obtained as the N\'eel temperature tends to zero. If the vector $\mathbf{Q}$ is commensurate with the lattice (umklapp with $\mathbf{Q}=\mathbf{G}/2$), pairs of electrons can be transferred between the pockets. This process may lead to superconductivity and a superconducting dome above the quantum critical point. We investigate the conditions under which such a dome arises. The specific heat is studied as a function of temperature and nesting mismatch, and the crossover from Fermi liquid to non-Fermi liquid is obtained.