Table 1 Experimental and calculated material parameters in Bi-III and in the reference materials In5Bi3 and Ca3Rh4Sn13 (see text).

The coherence length ξexp is obtained from the upper critical field and can be compared to ξcalc = vF/(πΔ). The Fermi velocity vF is estimated by scaling the density functional theory (DFT) estimate Embedded Image by (1 + λρ)−1, where λρ, the electron-phonon coupling constant obtained from the slope of ρ(T) with the help of a DFT estimate of the plasma frequency Ωp (see text), is listed separately. In In5Bi3 and Ca3Rh4Sn13, it can be compared to the ratio of measured and calculated Sommerfeld coefficients λC = γexpDFT−1. In Bi-III, no heat capacity data are as yet available. The gap size 2Δ = ηkBTc with η = 5.7 for Ca3Rh4Sn13 (27) and values ≃ 5 and 4 assumed for Bi-III and In5Bi3 (Supplementary Materials). n/a, not applicable.

Tc
(K)
Bc2
(T)
ξexp
(Å)
ξcalc
(Å)
Ωp
(eV)
λρλC
Bi-III7.052.451161723.52.75n/a
In5Bi34.140.33315002.51.250.90
Ca3Rh4Sn138.04.0911262.21.10.80