Charge density wave in a transverse electric field

A transverse electric field (a field perpendicular to the quasi-one-dimensional conducting chains) applied to a charge density wave (CDW) has similarities with a magnetic field applied to a superconductor : both cause frustration in the ordered state and, thus, can induce various intriguing states. We study the equilibrium states of CDW in a transverse electric field employing Ginzburg-Landau type effective free energy of the ordered state. We found that there are two types of CDW, corresponding to type-I and type-II superconductivity : in type-I CDW, the order is completely destroyed in the surface region as we increase the transverse field, whereas in type-II CDW, the dislocations (topological defects) are created, thus avoiding the complete destruction of the order. We discuss the condition for type-I and type-II CDW