Description
Recently a large class of novel low-dimensional materials have been synthesized, some of which undergo superconducting transitions. It is well known that electron-phonon coupling plays important role in low-dimensional materials, including macromolecules and (semi)conducting compounds. This interaction leads to polaron effect and self-trapping of charge carriers in soliton state at intermediate values of the interaction. At very low concentrations of charge carriers, they form bisolitons as singlet states of two bound electrons. With concentration increasing the wave functions of bisolitons start to overlap and they form a periodic collective state as a cnoidal wave. This state is separated from the state of free charge carriers by the gap which non-monotonously depends on the carriers concentration. The values of optimal and critical concentrations are calculated.
Such bisoliton mechanism of superconductivity explains also pressure dependence of superconducting transitions in some materials [1].
Acknowledgement: This work is done in frame of the project of the National Academy of Sciences of Ukraine, registration number 0122U000887. The author expresses sincere thanks to the sponsors of the International Conference “Science and Technology of Superconductivity” (October 26-27, Uppsala, Sweden) for the financial support.
- L.S. Brizhik, Electron correlations in molecular chains. Chapter 15. In: Correlations in Condensed Matter under Extreme Conditions, Eds. G. G. N. Angilella and A. La Magna, Springer, 2016, pp. 191-207. DOI:/10.1007/978-3-319-53664-4_15
