Impurity pinning of charge-density waves and spin-density waves

We reexamine the threshold electric field of the charge-density wave (CDW) within the Fukuyama-Lee-Rice model, where the temperature dependence of the effective Hamiltonian for the phase {φ} of the CDW is explicitly included. Our theory describes very well the temperature dependence of the threshold field in NbSe₃ when the effects of the thermal fluctations of {φ} are included. An extension of the model for the spin-density wave predicts that the threshold electric field in the spin-density wave does not exhibit a divergence at T=Tc but is almost constant for T{≤}0.5Tc and slightly increases ({~}33%) near T=Tc.