Transport near antiferromagnetic quantum-phase transitions in metals

The resistivity rho at the antiferromagnetic quantum critical point of meta ls displays strong deviations from Fermi liquid behavior with rho infinity T-x, 1 less than or similar to alpha less than or similar to 1.5, at low te mperatures T. A possible explanation for this behavior is the competition o f weak, but isotropic impurity scattering and strong scattering from spin-f luctuations. The latter is, however, only effective in very small regions o f 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 la rge regime with rho approximate to rho (0) + T(3/2)f(T/rho (0), (p - p(c))/ rho (0), B/rho (3/2)(0)), where rho (0) is the residual resistivity, B the magnetic field and p - p(c) > 0 measures the distance from the quantum-crit ical point on the paramagnetic side of the phase diagram. In a large regime , a linear temperature dependence of the resistivity rho infinity root rho T-0 is predicted with a magneto-resistivity linear in /B/. These results ar e compared to experiments and further tests are proposed. (C) 2001 Elsevier Science B.V. All rights reserved.