The quasi one-dimensional organic conductor (TMTTF)2AsF6 shows the charge ordering transition at Tc101K to a state of the ferroelectric Mott insulator which is still well conducting. We present and interpret the experimental data on the gigantic diel
ectric response in the vicinity of TCO, concentrating on the frequency dependence of the inverse $1/epsilon$ of the complex permittivity $epsilon=epsilon^prime+iepsilon^{primeprime}$. Surprisingly for a ferroelectric, we could closely approach the 2nd order phase transition and to deeply reach the critical dynamics of the polarization. We could analyse the critical slowing-down when approaching Tc from both sides and to extract the anomalous power law for the frequency dependence of the order parameter viscosity. Moreover, below Tc we could extract a sharp absorption feature coming from a motion of domain walls which shows up at a frequency well below the relaxation rate.
Interlayer tunneling in graphite mesa-type structures is studied at a strong in-plane magnetic field $H$ up to 55 T and low temperature $T=1.4$ K. The tunneling spectrum $dI/dV$ vs. $V$ has a pronounced peak at a finite voltage $V_0$. The peak positi
on $V_0$ increases linearly with $H$. To explain the experiment, we develop a theoretical model of graphite in the crossed electric $E$ and magnetic $H$ fields. When the fields satisfy the resonant condition $E=vH$, where $v$ is the velocity of the two-dimensional Dirac electrons in graphene, the wave functions delocalize and give rise to the peak in the tunneling spectrum observed in the experiment.
The dynamical properties of longitudinal and transverse conduction of NbSe$_3$ single-crystals have been simultaneously studied when the current is applied along the b axis (chain direction). In the vicinity of the threshold electric field for CDW sl
iding, the transverse conduction sharply decreases. When a rf field is applied, voltage Shapiro steps for longitudinal transport are observed as usual, but also current Shapiro steps in the transverse direction. The possible mechanisms of this effect are discussed.
