Editing Superconductivity (section)

=== Theory of operation ===
A superconductor is ''[[Conventional superconductor|conventional]]'' if it is driven by electron–phonon interaction and explained by the [[BCS theory]] or its extension, the Eliashberg theory. Otherwise, it is ''[[Unconventional superconductor|unconventional]]''.<ref>{{Cite journal |last=Gibney |first=Elizabeth |author-link=Elizabeth Gibney |date=5 March 2018 |title=Surprise graphene discovery could unlock secrets of superconductivity |department=News |journal=Nature |volume=555 |issue=7695 |pages=151&ndash;152 |bibcode=2018Natur.555..151G |doi=10.1038/d41586-018-02773-w |pmid=29517044 |quote=Superconductors come broadly in two types: conventional, in which the activity can be explained by the mainstream theory of superconductivity, and unconventional, where it can't. |doi-access=free}}</ref><ref>{{Cite journal |last1=Hirsch |first1=J. E. |last2=Maple |first2=M. B. |last3=Marsiglio |first3=F. |date=2015-07-15 |title=Superconducting materials classes: Introduction and overview |url=https://www.sciencedirect.com/science/article/pii/S0921453415000933 |journal=Physica C: Superconductivity and Its Applications |series=Superconducting Materials: Conventional, Unconventional and Undetermined |volume=514 |pages=1–8 |arxiv=1504.03318 |bibcode=2015PhyC..514....1H |doi=10.1016/j.physc.2015.03.002 |issn=0921-4534}}</ref> Alternatively, a superconductor is called unconventional if the superconducting [[order parameter]] transforms according to a non-trivial [[irreducible representation]] of the system's [[point group]] or [[space group]].<ref name="c7182">{{cite book |last1=Mineev |first1=V.P. |title=Introduction to Unconventional Superconductivity |last2=Samokhin |first2=K |date=1999-09-21 |publisher=CRC Press |isbn=978-90-5699-209-5 |publication-place=Amsterdam |pages=vii, 20}}</ref>