TITLE:
High-Temperature Superconductivity—An Electron Transfer Phenomenon
AUTHORS:
Joachim Sonntag
KEYWORDS:
High-Tc Superconductor, Electron Transfer, Electron Density, Hole Density, “P = 1/8” Anomaly, Jahn-Teller Effect
JOURNAL NAME:
World Journal of Condensed Matter Physics,
Vol.14 No.4,
November
4,
2024
ABSTRACT: The increase of the critical temperature Tc for superconductivity in Al1−x(SiO2)x cermets with increasing x correlates with a decrease of the electron density n due to electron transfer, expressed by
T
c
/
T
c,max
=1−γ⋅
n
2
(*). Behind the formula (*) and
T
c
/
T
c,max
=1−82.6
(
P−0.16
)
2
, which is characteristic of hole-doped cuprat high-temperature superconductors, lies a general phenomenon, namely electron transfer, which equalizes potential differences in the material and leads to a strong reduction of n. P is the fraction of holes filled by the transferred electrons. A quantitative consideration gives
T
c
(
x
)/
T
c,max
=1−
(
1−x
1−
x
0
)
2
(**), where x is the doping concentration and x0 is the concentration at which superconductivity begins. At
x=
x
max
=1
the electron source is completely depleted and with further growth of x the hole density p starts to increase and Tc decreases until superconductivity disappears completely at
x=2−
x
0
. Taking into account the formula (**), the hypothesis arose that for
x>
x
max
T
c
/
T
c,max
=1−γ⋅
p
2
(***), an analogue of the formula (*), and that superconductivity is possible not only by electron-Cooper pairs but also by paired holes. The mechanisms described here for HTSC suggest an analogy to the physics of semiconductors and that of nanocomposites: Electron-hole duality. The “
P=1/8
” anomaly in YBa2Cu3O6+x is caused by the simultaneous presence of electrons and holes, a consequence of incomplete electron transfer.