Showing papers by "S. Roth published in 1981"
TL;DR: The absence of the Knight-shift below the critical concentration of 7 % is in good agreement with the previously reported lack of Pauli-paramagnetism and hence confirms the existence of a novel mechanism of electrical conductivity with spinless charge carriers in the doping range from 1 to 7 % as discussed by the authors.
33 citations
TL;DR: In this paper, the specific heat and thermal conductivity of polyacetylene from liquid helium to room temperature were measured and it was shown that the polymer chains are oriented parallel to the well-known fibers in polyethylene.
Abstract: Measurements of the specific heat and of the thermal conductivity of pure and iodine doped polyacetylene from liquid helium to room temperature are reported. The thermal conductivity rises linearly from 3 to 50 K and with about the third power of the temperature from 50 to 300 K. The kink at 50 K corresponds to a very unusual minimum of the phonon mean free path, probably caused by resonant scattering of fast thermal phonons (which travel along the chains) on low frequency interchain modes. These results suggest that the polymer chains are oriented parallel to the well-known fibers in polyacetylene.
10 citations
TL;DR: In this paper, the magic angle spinning technique was used to record the NMR spectra of cis-(CH)x bi-solitons or bi-polarons and a line shift of about 30 ppm was found.
Abstract: NMR spectra on 18C of cis-(CH)x have been recorded using the magic angle spinning technique. Inspite of doping with AsF5 up to a level of ∼ 7at%, (CH)x does not convert to the trans modification. No Knight shift or other line shift is observed up to this dopant concentrtion. Above 7at% a line shift of about 30 ppm is found. To extend the soliton model to cis-(CH)x bi-solitons or bi-polarons are proposed.
7 citations
01 Jan 1981
TL;DR: In this paper, the authors measured the Pauli spin susceptibility of polymers with conjugated double bonds to study the electronic properties of metallic polymers by measuring the electrical conductivity of the polymers.
Abstract: It is well known that doping of polymers with conjugated double bonds leads to metallic conductivity [1], but the mechanism of the insulator-tometal transition and of the electric conductivity is not yet understood. The present work is an attempt to study the electronic properties of metallic polymers by measuring the Pauli spin susceptibility.
1 citations