Superheating field of clean superconductors near the type-I-type-II boundary: The low-temperature Meissner stability limit of niobium
Year: 2026
Type: article
Abstract: We calculate the low-temperature superheating field $B_{\rm sh}$ of clean superconductors near the boundary between type-I and type-II superconductivity, with particular emphasis on Nb. Ginzburg--Landau theory is not applicable at low temperatures, while previous microscopic calculations have been limited to either the large-$κ$ regime or the dirty limit. The clean, low-$κ$ regime relevant to Nb has therefore remained unresolved. We solve the self-consistent nonlinear nonlocal Eilenberger problem for the Meissner state and then analyze its stability against small perturbations. For a Nb-like material with $κ_{\rm GL}=0.7$, we obtain $B_{\rm sh}\simeq 290\,{\rm mT}$ at $T/T_c=0.2$, using $B_{c0}\simeq 200\,{\rm mT}$. For a TESLA-shaped Nb accelerator cavity, this corresponds to an intrinsic Meissner-stability limit of about $67\,{\rm MV/m}$.
DOI: 10.1103/2hv4-v8wf
Author: Takayuki Kubo
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7164190194