Effect of local inhomogeneity on nucleation: case of CDW depinning

Effects of spatial inhomogeneities on the nucleation process are studied th eoretically by considering the case of the depinning of charge density wave s (CDWs) as a typical example. In this case a nucleation is defined as the local appearance of the moving state in the pinned state. The depinning fie ld of the one-dirnensional (1D) commensurate CDW with one impurity is exami ned based on the phase Hamiltonian at absolute zero. The classical depinnin g field is lowered by a finite amount compared to that in the absence of th e impurity. The quantum depinning in our model is also discussed. It turns out the impurity assists the quantum depinning. (C) 2000 Elsevier Science B .V. All rights reserved.