Prediction of Universal Peak in Electronic Thermal Conductivity of High Temperature Superconductors via Dipolon Theory

The dipolon
theory [1-4]
has predicted
the two high energy and one low energy
quasiparticle (QP) kinks
besides
a new very low energy kink
in
hIgh $T_C$ superconductors
(HTSCs).
Here we report the prediction of a
universal peak
in electronic thermal conductivity
(ETC)
of
HTSCs.
We find that
the ETC
in HTSCs is due to
the rate of enhancement
with
temperature
of the
QP energy distribution
particularly near
the M point of the Fermi level (high QP density region),
which becomes maximum at the
temperature
$T^{(peak)}$ given by
$x = ln( \frac {x+2}{x-2})$
where
$ x = \Delta (0) /k_BT^{(peak)}$
yielding
$ T^{(peak)} = \Delta (0) /2.40 k_B. $
This peak
is valid for all HTSCs and for all directions
of ETC in the a-b plane and hence is a
universal peak.
For HTSCs where
$\Delta (0) = 1.5k_BT_C $,
we have
$T^{(peak)}
=0.6 T_C$,
in agreement with the experimental results [5]
$T^{peak}_{expt}
/T_C = 0.6 \pm 0.2. $
(1) R. R. Sharma, Phy. Rev. {\bf B 63}, 054506 (2001).
(2) R. R. Sharma, Physica {\bf C 439}, 47 (2006).
(3) R. R. Sharma, Physica {\bf C 468}, 190 (2008).
(4) R. R. Sharma, "Dipolon Theory of Kink Structure
...", in "Superconducting ...", Ed. K. N. Courtlandt,
P. 81-100, Nova Sc, Pub., Inc., New York, 2009.
(5) C. Uher, in "Phys. Propertie ...",
Ed. D. M. Ginsberg ~W. Sci., Singapore,
1993, Vol. III.