Dimensional Charge Density Wave Research Articles

Collective transport of spin density waves in organic salts

The spin density wave (SDW) in organic conductors like (TMTSF) 2PF 6 possesses two distinct collective modes; the spin wave and the sliding mode. Since the spin dynamics of SDW is described by an equation similar to the Leggett equation for superfluid 3He, we predict the longitudinal resonance. On the other hand both the electric charge and the current couple to the sliding SDW mode, which gives rise to a variety of nonlinear phenomena similar to those found in the quasi-one dimensional charge density wave (CDW) like NbSe 3.

Sound Propagation in Cdw and Sdw

ABSTRACTWe present a microscopic theory of the sound propagation in quasi one dimensional charge density wave (CDW), spin density wave (SDW) and field induced spin density wave (FISDW). First, we consider the ideal situation that the phase correlation length in the CDW or the SDW is infinite. In this limit due to the diffusion pole at iω = Dq2 in a variety of correlation functions the sound propagation depends on a) what is the ratio ω/Dq2 and b) if the CDW (or the SDW) is pinned or unpinned where D is the diffusion constant. Second, when the CDW (or the SDW) is unpinned, the phason starts to participate in the screening of the ionic potential. However, since the unpinned part is strongly inhomogeneous, the contribution of the phason term depends on the wave vector of q of the sound wave like (1 + (Lq)2)−1 where L is the Fukuyama-Lee-Rice coherence length. The present theory accounts for a variety of features observed in sound propagation in quasi-one dimensional CDW systems like NbSe3 and TaS3.

Electron Tunneling in Charge-Density and Spin-Density Waves

ABSTRACTFirst we calculate the tunneling density of states of quasi-two dimensional charge density waves (CDW) or spin density waves (SDW) in the presence of impurity scattering. Second, we consider the tunneling current between two CDWs or two SDWs. We point out the existence of new contribution, which gives rise to the a.c. current when one CDW is sliding relative to the other one.

Collisions Between Solitary Wave Solutions to a Double Sine-Gordon Equation

Evolution of one dimensional charge density waves in organic conductors can be described by a double sine-Gordon equation. Interaction between solitary wave solutions (2π-kinks and 2π-antikinks) of this equation is examined numerically. Waves of the same kind show a quasi-solitonic behaviour, i.e., the waves survive the collision, and only a minor change in energy and momentum is observed. The result of the interaction between waves of different kind depends on the initial velocity of the interacting waves. For velocities less than a certain threshold velocity the waves enter a breather-like mode which rapidly dies out, while for larger velocities the waves show a quasisolitonic behaviour.

Sound Waves, Phason and Screening Effect in One Dimensional Charge Density Wave

The screening mechanisms are studied on one-dimensional electron-ion system with a charge density wave. The phason-phonon coupling drastically alters a phonon and a phason which are given without its consideration. The dispersion relations of them are given for a whole temperature region of a charge density wave.