Incommensurability effects

Figure 5 Typical velocity relationship of kinetic friction for a sliding contact in which friction is from adsorbed layers confined between two incommensurate walls. The kinetic friction F is normalized by the static friction Fs. At extremely small velocities v, the confined layer is close to thermal equilibrium and, consequently, F is linear in v, as to be expected from linear response theory. In an intermediate velocity regime, the velocity dependence of F is logarithmic. Instabilities or pops of the atoms can be thermally activated. At large velocities, the surface moves too quickly for thermal effects to play a role. Time-temperature superposition could be applied. All data were scaled to one reference temperature. Reprinted with permission from Ref. 25. 

The effect of dimensionality was also considered in that study. It was found that systems with commensurate 2-D walls yield results that are similar to the 1-D case because the interference between Vt and V[, persists. This situation is no longer true for the incommensurate case, where the adsorbed atoms can circumnavigate the points of maximum lateral force, which permits first-order instabilities regardless of the nature of the higher order harmonics in the wall-atom potential. Thus, one would expect friction to remain finite as Vq... 

Ex situ LEED and XPS studies were conducted to demonstrate the effects of CUand Br" these anions form densely packed incommensurate structures on Cu underpotential deposition at the full monolayer. ... 

The FvdM as well as the BMVW model neglects thermal fluctuation effects both are T = 0 K theories. Pokrovsky and Talapov (PT) have studied the C-SI transition including thermal effects. They found that, for T 0 K the domain walls can meander and collide, giving rise to an entropy-mediated repulsive force of the form F where I is the distance between nearest neighbor walls. Because of this inverse square behavior, the inverse wall separation, i.e. the misfit m, in the weakly incommensurate phase should follow a power law of the form... 

Kawamoto T, Mori T, Terakura C, Terashima T, Uji S, Takimiya K, Aso Y, Otsubo T (2003) Incommensurate anion potential effect on the electronic states of the organic superconductor (MDT-TSF)(Aul2)o.436- Phys Rev B 67 020508/1-4... 

On the other hand, it may be used a secondary effect, namely creation of deformation (distortion) wave in the copper oxide sample, which because of above should lead to the formation of CDW (and hence SDW) state in the volume of a sample with corresponding increase in Tc. It seems likely that namely such methods was used in [18] where thin (15 nm) film of LSCO was grown with block-by-block molecular epitaxy (defect-free growth process) on SrLaAl04 substrate which lattice period is only somewhat different from that of grown film. Such incommensurability results in... 

Abstract Electronic correlation effects in La2.ISrINi04 lead to spontaneous phase separation into microscopic spin/charge stripes with commensurate or incommensurate order. Raman scattering experiments on such single crystalline materials show a rich phenomenology of phonon and magnon anomalies due to the new, self-organized periodicities. These effects are observable as function of temperature. 

The highest induction effect should be expected in the case of inequality w3 vv2 fulfillment at nq > w2. In this regard, accumulation of final products by the overall reaction (2.15b), No. 2 under the condition of effective induction performance must proceed at an incommensurately higher rate than the primary one. As mentioned above, the induction effect at w2 w3 will be insignificant, approaching the limit I = 0. In this consideration, it is assumed that rate constants ku k2 and k2 characterize elementary reactions of the same kinetic order otherwise, concentration factors would also have to be taken into account which would necessarily complicate the analysis. 

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