Gaps in unconventional superconductors
arXiv:2607.26251
The paper reviews how the energy gap behaves in unconventional superconductors, explaining the non‑uniform gap structure, its origins, and how it appears in experimental measurements.
Abstract
The energy gap is one of the defining properties of a superconductor and appears because the quasiparticle excitations radically change once a metallic system enters the superconducting state. Unconventional superconductors typically exhibit a non-uniform gapping and therefore show physical effects that are subject to intense research. In this review, we provide an overview of concepts needed to understand how unconventional superconductors are different from conventional ones, where the gapping comes from and how it expresses itself in experimentally accessible quantities. This should give the basis to understand current open research questions and navigate the recent literature that tend to contain contradictory conclusions.
34 pages, 15 figures, a pedagogical article to review and introduce the topic