Quantum Correction to Conductivity Close to a Ferromagnetic Quantum Critical Point in Two Dimensions

We study the temperature dependence of the conductivity due to quantum interference processes for a two-dimensional disordered itinerant electron system close to a ferromagnetic quantum critical point. Near the quantum critical point, the crossover between diffusive and ballistic regimes of quantum interference effects occurs at a temperature $T^{*}=1/\tau \gamma (E_F\tau {)}^2$, where $\gamma$ is the parameter associated with the Landau damping of the spin fluctuations, $\tau$ is the impurity scattering time, and $E_F$ is the Fermi energy. For a generic choice of parameters, $T^{*}$ is smaller than the nominal crossover scale $1/\tau$. In the ballistic quantum critical regime, the conductivity behaves as $T^{1/3}$.

Figure 1

Different crossover regimes for the temperature dependence of the triplet channel contribution to conductivity. $T_{\delta 1}=({\delta }^{3/2}/\gamma )E_F$, $T_{\delta 2}=({\delta }^2\tau /\gamma )E_F^2$, $T_2=E_F{\delta }^{1/2}$. Notice that ${\gamma }^{1/2}\gg 1/(E_F\tau )$.