2025/11/14 by Anton Talkachov, Paul Leask, Talkachov, Anton +4
Physics and Astronomy · #Coherence (philosophical gambling strategy) #Coherence length #Correlation #Magnetic field #Pairing #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Scale (ratio) #Square lattice #Superconducting coherence length #Superconductivity #Topological Materials and Phenomena #Vortex #Work (physics)
paper · pdf · open access · doi:10.1103/bf2v-wtkt
published in Physical review. B./Physical review. B 113(22) (American Physical Society)
openalex publication_date 2026/05/11 · openalex created_date 2026/05/12 · openalex updated_date 2026/05/12
The ratio of magnetic field penetration length <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mi>λ</a:mi> </a:math> and superconducting coherence length <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mi>ξ</b:mi> </b:math> is a defining quantity that governs magnetic response and underpins the conventional type-I and type-II classification of superconductors. While multicomponent superconductors are known to exhibit multiple coherence lengths with rich and often exotic behavior, single-component superconductors are traditionally assumed to be fully characterized by a single Ginzburg-Landau parameter. Here we revisit this concept. We demonstrate that even nominally single-component superconductors are, in general, intrinsically characterized by multiple coherence lengths. Specifically, we analyze a common physical situation in which a subdominant pairing channel is fully suppressed in the ground state, yielding a nominally single-component superconducting ground state. We show that, nonetheless, proximity to a competing pairing instability generically gives rise to multiple correlation lengths with a nontrivial hierarchy. This has consequences for all inhomogeneous states. Especially near a competing pairing instability, the magnetic field penetration depth lies between two distinct coherence lengths, leading to a breakdown of the conventional type-I and type-II dichotomy and enabling the coexistence of vortex clusters and Meissner domains. More broadly, we find that superconducting states cannot, in general, be classified by a single fundamental length scale, even in ostensibly conventional single-component systems.