Abstract
Abstract
The superfluid density $$n_{s}(T)$$
n
s
(
T
)
of a superconductor is calculated based on the generalized Bose–Einstein condensation (GBEC) theory that addresses a fully-interacting ternary boson-fermion gas mixture of free electrons as fermions, plus two-electron Cooper pairs (2eCPs) and also, explicitly, two-hole Cooper pairs (2hCPs), both as bosons. Here we consider two special cases (i) 100%–0% (i.e., with no condensed 2hCPs) and (ii) 0%–100% (i.e., with no condensed 2eCPs). Subsumed in GBEC are the Bardeen–Cooper–Schrieffer (BCS) and Bose–Einstein condensation (BEC) theories along with the BCS-BEC crossover theory extended with 2hCPs. We find that in the weak-coupling regime $$n_{s}(0)$$
n
s
(
0
)
agrees with data from the Uemura et al. (2004) graph for several elemental SCs by taking in 3D with a quadratic energy-dispersion relation while in 2D with a linear relation are much too far below the data. In the strong-coupling regime the linear behavior of critical temperature $$T_{c}$$
T
c
vs $$n_{s}(0)$$
n
s
(
0
)
obtained here is just as Božović et al. (2016) found. However, in 2D with a linear relation accounting for 0%–100%, $$n_{s}(T)/n_{s}(0)$$
n
s
(
T
)
/
n
s
(
0
)
compares well with some high-$$T_{c}$$
T
c
-cuprate SC data between the two coupling regimes.
Funder
Consejo Nacional de Ciencia y Tecnología
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México
Publisher
Springer Science and Business Media LLC
Subject
General Earth and Planetary Sciences,General Physics and Astronomy,General Engineering,General Environmental Science,General Materials Science,General Chemical Engineering