Superconducting Device with Enhanced Sensitivity

Superconducting Device with Enhanced Sensitivity

      In the prior art, three terminal devices are known in
which electric fields are used to control the transport properties of
channel layers consisting of high-Tc superconducting materials.  The
sensitivity of these or similar devices may be enhanced if materials
are used for the channel layer which have an intrinsic concentration
n of mobile charge carriers which is either higher or lower than the
carrier concentration in standard high-Tc superconductors which are
usually optimized for high critical temperatures.

      The sensitivity of such field-effect devices is characterized
by the change of the critical temperature WTc of Tc per applied gate
voltage WV.  WTc is given by:
and can therefore be enhanced by utilizing superconductors with a
high value of the transfer function wTc/wn.

      A typical characteristic of the critical temperature Tc versus
the concentration n of free charge carriers for Tc superconductors is
shown in the figure (see [*]).  As can be seen in the figure, a high
value of the function wTc/wn and, hence, a high sensitivity of the
field-effect devices is obtained if superconducting materials are
selected for the source-drain channel which have a carrier
concentration which is either higher or lower than the value required
to maximize Tc .

      Reference
(*)  J. B. Torrance, Y. Tokura, A. I. Nazzal, A. Bezinge, T. C. Huang
and S. S. P. Parkin, "Anomalous Disappearance of Hig...