Volume 118, Number 3, May 2017
|Number of page(s)||7|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||12 July 2017|
Possible Fano resonance for high-Tc multi-gap superconductivity in p-Terphenyl doped by K at the Lifshitz transition
1 RICMASS, Rome International Center for Materials Science Superstripes - Via dei Sabelli 119A, 00185 Rome, Italy
2 Institute for Microelectronics and Microsystems, IMM, Consiglio Nazionale delle Ricerche CNR Via del Fosso del Cavaliere 100, 00133 Roma, Italy
3 Institute of Crystallography, IC, Consiglio Nazionale delle Ricerche CNR - via Salaria, Km 29.300, 00015 Monterotondo Roma, Italy
4 Department of Chemistry, University of Liverpool - Liverpool, L69 7ZD, UK
5 School of Pharmacy, Physics Unit, University of Camerino - Camerino, Italy
6 National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) 115409 Moscow Kashirskoe shosse 31, Russia
7 Latvian Academy of Sciences - Akadēmijas Laukums 1, Rīga, LV-1050 Latvia
Received: 25 May 2017
Accepted: 22 June 2017
Recent experiments have reported the emergence of high-temperature superconductivity with critical temperature Tc between 43 K and 123 K in a potassium-doped aromatic hydrocarbon para-Terphenyl or p-Terphenyl. This achievement provides the record for the highest Tc in an organic superconductor overcoming the previous record of Tc = 38 K in Cs3C60 fulleride. Here we propose that the driving mechanism is the quantum resonance between superconducting gaps near a Lifshitz transition which belongs to the class of Fano resonances called shape resonances. For the case of p-Terphenyl our numerical solutions of the multigap equation shows that high Tc is driven by tuning the chemical potential by K doping and it appears only in a narrow energy range near a Lifshitz transition. At the maximum critical temperature, Tc = 123 K, the condensate in the appearing new small Fermi surface pocket is in the BCS-BEC crossover while the Tc drops below 0.3 K where it is in the BEC regime. Finally, we predict the experimental results which can support or falsify our proposed mechanism: a) the variation of the isotope coefficient as a function of the critical temperature and b) the variation of the gaps and their ratios 2Δ/Tc as a function of Tc.
PACS: 74.70.Kn – Organic superconductors / 74.20.-z – Theories and models of superconducting state / 74.10.+v – Occurrence, potential candidates
© EPLA, 2017
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