Infrared ellipsometry study of the charge dynamics in K3p-terphenyl
DOKPE
- He, Qi ORCID University of Fribourg
- Marsik, P. University of Fribourg
- Mardelé, F. Le University of Fribourg
- Xu, B. ORCID University of Fribourg
- Sharma, M. ORCID University of Camerino, Italy
- Pinto, N. ORCID University of Camerino, Italy
- Perali, A. ORCID University of Camerino, Italy
- Nicola, C. Di ORCID University of Camerino, Italy
- Pettinari, C. University of Camerino, Italy
- Baeriswyl, D. ORCID University of Fribourg
- Bernhard, C. ORCID University of Fribourg
- 2023
Submitted to:
- Physical Review B (condensed matter and materials physics) (PRB). - College Park, USA: American Physical Society. - 2023, vol. 107, no. art. 094520, p. 1-13
English
We report an infrared ellipsometry study of the charge carrier dynamics in polycrystalline K𝑥𝑝-terphenyl samples with nominal 𝑥=3, for which signatures of high-temperature superconductivity were previously reported. The infrared spectra are dominated by two Lorentzian bands with maxima around 4000 and 12 000 cm−1 which, from a comparison with calculations based on a Hückel model, are assigned to intramolecular excitations of 𝜋 electrons of the anionic 𝑝-terphenyl molecules. The intermolecular electronic excitations are much weaker and give rise to a Drude peak and a similarly weak Lorentzian band around 220 cm−1. A dc resistivity of about 0.3 Ωcm at 300K is deduced from the IR data, comparable to values measured by electrical resistivity on a twin sample. The analysis of the temperature dependence of the low-frequency response reveals a gradual decrease of the plasma frequency and the scattering rate of the Drude peak below 300K that gets anomalously enhanced below 90K. The corresponding missing spectral weight of the Drude peak appears blueshifted towards the Lorentz band at 220 cm−1. This characteristic blueshift signifies an enhanced localization of the charge carriers at low temperatures and contrasts the behavior expected for a bulk superconducting state for which the missing spectral weight would be redshifted to a delta function at zero frequency that accounts for the loss-free response of the superconducting condensate. Our data might still be compatible with a filamentary superconducting state with a volume fraction well below the percolation limit for which the spatial confinement of the condensate can result in a plasmonic resonance at finite frequency.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
-
- English
- Classification
- Physics
- License
- CC BY
- Open access status
- green
- Identifiers
-
- DOI 10.1103/PhysRevB.107.094520
- ISSN 2469-9950
- ISSN 2469-9969
- Persistent URL
- https://folia.unifr.ch/unifr/documents/329626
Statistics
Document views: 17
File downloads:
- heqiphysrevb1070945202024.pdf: 51