title: Controlling the near-surface superfluid density in underdoped YBa2Cu3O(6+x) by photo-illumination.
abstract: The interaction with light weakens the superconducting ground state in classical superconductors. The situation in cuprate superconductors is more complicated: illumination increases the charge carrier density, a photo-induced effect that persists below room temperature. Furthermore, systematic investigations in underdoped YBa2Cu3O(6+x) (YBCO) have shown an enhanced critical temperature Tc. Until now, studies of photo-persistent conductivity (PPC) have been limited to investigations of structural and transport properties, as well as the onset of superconductivity. Here we show how changes in the magnetic screening profile of YBCO in the Meissner state due to PPC can be determined on a nanometer scale utilizing low-energy muons. The data obtained reveal a strongly increased superfluid density within the first few tens of nanometers from the sample surface. Our findings suggest a non-trivial modification of the near-surface band structure and give direct evidence that the superfluid density of YBCO can be controlled by light illumination.
authors.affiliation: 1] Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland [2] Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Stilp
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Suter
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Prokscha
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Salman
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Morenzoni
authors.affiliation: Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Keller
authors.affiliation: 1] Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany [2] Institute for Metallic Materials, IFW Dresden, D-01069 Dresden, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Pahlke
authors.affiliation: Institute for Metallic Materials, IFW Dresden, D-01069 Dresden, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hühne
authors.affiliation: Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Bernhard
authors.affiliation: 1] Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8.
authors.forename: Ruixing
authors.initials: R
authors.lastname: Liang
authors.affiliation: 1] Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8.
authors.forename: W N
authors.initials: WN
authors.lastname: Hardy
authors.affiliation: 1] Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8.
authors.forename: D A
authors.initials: DA
authors.lastname: Bonn
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: J C
authors.initials: JC
authors.lastname: Baglo
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: R F
authors.initials: RF
authors.lastname: Kiefl