title: Optically induced lattice deformations, electronic structure changes, and enhanced superconductivity in YBa2Cu3O6.48.
abstract: Resonant optical excitation of apical oxygen vibrational modes in the normal state of underdoped YBa2Cu3O6+xinduces a transient state with optical properties similar to those of the equilibrium superconducting state. Amongst these, a divergent imaginary conductivity and a plasma edge are transiently observed in the photo-stimulated state. Femtosecond hard x-ray diffraction experiments have been used in the past to identify the transient crystal structure in this non-equilibrium state. Here, we start from these crystallographic features and theoretically predict the corresponding electronic rearrangements that accompany these structural deformations. Using density functional theory, we predict enhanced hole-doping of the CuO2planes. The empty chain Cudy2-z2orbital is calculated to strongly reduce in energy, which would increase c-axis transport and potentially enhance the interlayer Josephson coupling as observed in the THz-frequency response. From these results, we calculate changes in the soft x-ray absorption spectra at the CuL-edge. Femtosecond x-ray pulses from a free electron laser are used to probe changes in absorption at two photon energies along this spectrum and provide data consistent with these predictions.
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter , Hamburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Mankowsky
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter , Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Fechner
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter , Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Först
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter , Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: von Hoegen
authors.affiliation: Max Planck Institute for Solid State Research , Stuttgart, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Porras
authors.affiliation: Max Planck Institute for Solid State Research , Stuttgart, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Loew
authors.affiliation: Linac Coherent Light Source, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park, California 94025, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Dakovski
authors.affiliation: Linac Coherent Light Source, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park, California 94025, USA.
authors.forename: M
authors.initials: M
authors.lastname: Seaberg
authors.affiliation: Linac Coherent Light Source, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park, California 94025, USA.
authors.forename: S
authors.initials: S
authors.lastname: Möller
authors.affiliation: Linac Coherent Light Source, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park, California 94025, USA.
authors.forename: G
authors.initials: G
authors.lastname: Coslovich
authors.affiliation: Max Planck Institute for Solid State Research , Stuttgart, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Keimer
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus , Didcot OX11 0DE, United Kingdom.
authors.forename: S S
authors.initials: SS
authors.lastname: Dhesi
authors.forename: A
authors.initials: A
authors.lastname: Cavalleri