Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: SC: Tunnelling, Josephson Junctions

TT 31.1: Talk

Thursday, March 25, 2010, 09:30–09:45, H21

Tuning superconductivity by carrier injection — •P. Müller¹, Y. Koval¹, X. Y. Jin¹, C. Bergmann¹, Y. Simsek¹, L. Özyüzer¹, H. B. Wang², G. Behr³, and B. Büchner³ — ¹Department of Physics and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Germany — ²National Institute for Materials Science (NIMS), Tsukuba, Japan — ³IFW-Dresden, Germany

In layered high-temperature superconductors, like Bi₂Sr₂CaCu₂O_8+δ, superconductivity is controlled by carrier doping of the conducting planes. Usually this is achieved by a non-stoichiometric composition. Normally, current flow inside superconductors is never expected to be able to change the material itself. However, we were able to show that by extensive current injection along the c-axis the superconducting properties of Bi₂Sr₂CaCu₂O_8+δ can be changed effectively and reversibly. By injecting current perpendicular to the planes, we show that critical temperature, c-axis resistivity and critical current of intrinsic Josephson junctions can be tuned in a large range from underdoping to extreme overdoping. Apparently, the insulating layers are charged by injected carriers, and work as a floating gate. The result is hole doping of the conducting layers. This flash memory concept seems to be a general property of layered materials where the insulating charge reservoir layers are separated from the conducting planes.