Transport near antiferromagnetic quantum-phase transitions in metals

Abstract

The resistivity ρ at the antiferromagnetic quantum critical point of metals displays strong deviations from Fermi liquid behavior with ρ∝ T α , 1≲ α≲1.5, at low temperatures T. A possible explanation for this behavior is the competition of weak, but isotropic impurity scattering and strong scattering from spin-fluctuations. The latter is, however, only effective in very small regions of the Fermi surface. Non-linear orbital effects of a magnetic field can be used to study this in detail. The conductivity obeys a scaling form in a large regime with ρ≈ρ 0+T 3/2f (T/ρ 0, (p−p c )/ρ 0,B/ρ 0 3/2) , where ρ 0 is the residual resistivity, B the magnetic field and p− p c>0 measures the distance from the quantum-critical point on the paramagnetic side of the phase diagram. In a large regime, a linear temperature dependence of the resistivity ρ∝ ρ 0 T is predicted with a magneto-resistivity linear in | B|. These results are compared to experiments and further tests are proposed.