AC impedance of A4C60 fullerides under pressure
2015 (English)In: New Journal of Physics, ISSN 1367-2630, Vol. 17, no 2, 023010- p.Article in journal (Refereed) Published
Three A4C60 compounds, with A = Li, Na and K, have been studied by impedance spectroscopy between 100 K and 293 K at pressures up to 2 GPa. The results are in very good agreement with earlier DC resistance studies and with data from the literature. For all three materials the measured conductivity can be fitted by a sum of at least two Arrhenius terms. The band gaps derived from the resistance data, 0.3 eV for Na4C60 and 0.5 eV for K4C60, are in excellent agreement with data measured by other methods. For Li4C60, our results disagree with a recent suggestion that the conductivity is dominated by ionic conduction. Although a certain ionic component probably exists we suggest that electronic transport dominates in our samples at and below room temperature because the derived “activation energy” decreases under pressure, the derived “activation volume” is negative, and we observe neither a significant electrode blocking capacitance nor any significant metal transport under DC conditions.
Place, publisher, year, edition, pages
Institute of Physics (IOP), 2015. Vol. 17, no 2, 023010- p.
Fullerides, Li4C60, Na4C60, K4C60, high pressure, conductivity, resistivity, semiconductor, ionic conduction
Research subject Solid State Physics
IdentifiersURN: urn:nbn:se:umu:diva-99306DOI: 10.1088/1367-2630/17/2/023010OAI: oai:DiVA.org:umu-99306DiVA: diva2:786634
FunderSwedish Research Council, 621-2010-3732
Open Access journal2015-02-062015-02-062015-09-28Bibliographically approved