<
first
] <
prev
] [Phuan Ong (Princeton Univ.) 11] [
NEXT
> [
last
>
Part II. The Nernst effect in cuprates.
A brief introduction to the Nernst effect in the vortex state below
T
c. In the presence of a thermal gradient (-grad
T
) along the
x
-axis, vortices diffuse down the thermal gradient (in the vortex liquid state). We ignore the small angle that
v
_L (line velocity) makes with (-grad
T
). Each vortex that crosses the (broken) line between the voltage electrodes produces a phase slip of 2\pi. By the Josephson equation, the electrochemical potential between the voltage probes is given by 2
eV = (2\pi)dn/dt
(
n
is the number of vortices crossing the line), or equivalently,
E = B x v
_L. We refer to E_y produced by the phase slip as the vortex Nernst signal. The Nernst coefficient is the
E
-field detected in the
y
direction per unit field applied per unit gradient, viz.
v
= E_y/B|grad
T
|. The Nernst signal produced by vortex motion is a rather large signal (typically a few microVolts per Tesla-Kelvin), compared with the small signal associated with normal-state charge carriers. The latter is drastically reduced by what we call the 'Sondheimer cancellation' to be discussed later.
<
first
] <
prev
] [Phuan Ong (Princeton Univ.) 11] [
NEXT
> [
last
>
