APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011;
Dallas, Texas
Abstract: X1.00005 : Tuning superconductivity by carrier injection
4:54 PM–5:30 PM
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All high-T$_c$ cuprates are stacking sequences of CuO$_2$ layers
and charge reservoir layers consisting of metal oxides. Upon
doping the CuO$_2$ layers, antiferromagnetic order is destroyed
and metallic conductivity is established. Usually doping is
achieved by a non-stoichiometric composition of the charge
reservoir layer. However, we already have shown that we can
change the carrier concentration of Bi$_2$Sr$_2$CaCu$_2$O$_
{8+\delta}$ single crystals by current injection along the c-
axis [1]. Critical temperature, c-axis resistivity and critical
current of intrinsic Josephson junctions can be tuned in a large
range from underdoping to extreme overdoping. This effect is
persistent up to annealing temperatures of approximately 270 K.
Using current injection at higher bias, we were able to reduce
the carrier concentration again. We investigated in detail the
superconducting properties by performing macroscopic quantum
tunneling experiments of intrinsic Josephson junctions. The
experiments have been carried out repeatedly on samples, whose
properties were changed only by current injection. An
exponential increase of the critical current density with hole
concentration was observed. At the same time, the capacitance of
intrinsic Josephson junctions increased significantly. Finally,
only by current injection, we were able to convert into the
superconducting state a nonsuperconducting, oxygen depleted
sample.
This work was done in collaboration with Y. Koval, X.Y.
Jin, S. Probst, Y. Simsek, C. Steiner (Universit\"at Erlangen),
H. B. Wang (NIMS, Tsukuba), and G. Behr, B. B\"uchner (IFW
Dresden).
\\[4pt] [1] Y. Koval, X.Y. Jin, C. Bergmann, Y. Simsek, L.
\"Ozy\"uzer, P. M\"uller, H. B. Wang, G. Behr, B. B\"uchner,
Appl. Phys. Lett. \textbf{96}, 082507 (2010).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.X1.5