Visualizing the spatial structure of charge density waves via scanning electron microscopy

Heinz, G.; Parisi, J.; Pokrovskiǐ, V. Ya.; Kittel, A.

doi:10.1016/s0921-4526(02)00471-4

Cited by 1 publication

(1 citation statement)

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“…In cases when a more narrow light spot was used, we frequently observed large differences in ⌬R as the spot was scanned across the sample width, in some cases even changing sign. Similarly, large local changes in the chemical potential, implying local polarizations, varying across the sample width were measured with a scanning electron microscope, 27 presumably reflecting the sensitivity of the CDW to grain boundaries and surface features prevalent in even visually smooth samples of TaS 3 . (ii) For some cases, the measured frequency dependence of ⌬R / R did not obey Eq.…”

Section: Dynamics Of the Electroreflective Response …mentioning

confidence: 88%

Dynamics of the electroreflective response ofTaS3

Rai

Brill

2004

Phys. Rev. B

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We have observed a large ͑ϳ1%͒ change in infrared reflectance of the charge-density-wave (CDW) conductor, orthorhombic TaS 3 , when its CDW is depinned. The change is concentrated near one current contact. Assuming that the change in reflectance is proportional to the degree of CDW polarization, we have studied the dynamics of CDW repolarization through position-dependent measurements of the variation of the electroreflectance with the frequency of square-wave voltages applied to the sample, and have found that the response could be characterized as a damped harmonic oscillator with a distribution of relaxation (i.e., damping) times. The average relaxation time, which increases away from the contacts, varies with applied voltage as 0 ␣1/V p with p ϳ 3 / 2, but the distribution of times broadens as the voltage approaches the depinning threshold. Very low resonant frequencies ͑ϳ1 kHz͒ indicate a surprisingly large amount of inertia, which is observable in the time dependence of the change in reflectance as a polarity-dependent delay of ϳ100 s.

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Section: Dynamics Of the Electroreflective Response …mentioning

confidence: 88%