Jean-Marc Triscone awarded a honorary doctorate

by the Norwegian University of Science and Technology (NTNU)

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next Q-MAC meetings in 2018:

3rd Q-MAC symposium in Venice, May 22-25, 2018.

Next regular meeting in Paris, November 27-28, 2018.

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Publication Detail / Abstract

R. Mankowsky, A. Subedi, M. Först, S. O. Mariager, M. Chollet, H. T. Lemke, J. S. Robinson, J. M. Glownia, M. P. Minitti, A. Frano, M. Fechner, N. A. Spaldin, T. Loew, B. Keimer, A. Georges, A. Cavalleri

Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5

published in Nature on December 3, 2014
> Full text via publisher
Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures. In complex oxides, this method has been used to melt electronic order, drive insulator-to-metal transitions and induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in YBa2Cu3O6+x. Here we report the crystal structure of this exotic non-equilibrium state, determined by femtosecond X-ray diffraction and ab initio density functional theory calculations. We find that nonlinear lattice excitation in normal-state YBa2Cu3O6+x at above the transition temperature of 52 kelvin causes a simultaneous increase and decrease in the Cu–O2 intra-bilayer and, respectively, inter-bilayer distances, accompanied by anisotropic changes in the in-plane O–Cu–O bond buckling. Density functional theory calculations indicate that these motions cause drastic changes in the electronic structure. Among these, the enhancement in the dx2-y2 character of the in-plane electronic structure is likely to favour superconductivity.
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