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TT: Fachverband Tiefe Temperaturen

TT 62: Superconductivity: Properties, Electronic Structure, Order Parameter

TT 62.8: Vortrag

Donnerstag, 14. März 2013, 17:15–17:30, H19

Effect of photo-induced hole doping on the Meissner screening in underdoped YBa₂Cu₃O_7−δ — •Evelyn Stilp^1,2, Andreas Suter², Elvezio Morenzoni², Thomas Prokscha², Zaher Salman², Hugo Keller¹, Patrick Pahlke^3,4, Ruben Hühne⁴, Jordan C. Baglo⁵, Ruixing Liang⁵, and Robert F. Kiefl⁵ — ¹Physik-Institut, University of Zurich, CH-8057 Zurich, Switzerland — ²Laboratory for Muonspin Spectroscopy, PSI, CH-5232 Villigen PSI, Switzerland — ³Inst. für Festkörperphysik,TU Dresden, D-01069 Dresden, Germany — ⁴IFW Dresden, D-01069 Dresden, Germany — ⁵Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T

For classical superconductors the interaction with light results in a reduction of the energy gap due to excess of quasiparticles. Surprisingly, this is very different for cuprate superconductors where it was found that illumination with light increases the charge carrier density. Systematic investigations in YBa₂Cu₃O_7−δ showed that T_c is increased by this effect which is most pronounced at the heavily underdoped side of the phase diagram. Up to now studies of photo-induced processes have been restricted to investigations of transport properties and critical temperatures. Using low energy µSR changes in the Meissner screening profile caused by illumination were directly investigated. We will show that the photo-persistent effect in underdoped YBa₂Cu₃O_7−δ is related to an increase of the superfluid density close to the surface. We are also able to show that the oxygen ordering is a crucial ingredient of the photo-induced effect.