Dr. Clifford Hicks, Max Planck Institute, Dresden
Title: Effect of uniaxial stress on the superconductivity of YBa2Cu3O6+x and Sr2RuO4
Abstract: We use piezoelectric-based uniaxial pressure cells to apply tunable strains of up to ~1% to electronic materials. In this seminar, I will present results on two compounds. Sr2RuO4 is an unconventional superconductor with a critical temperature (at zero stress) of 1.5 K. Uniaxial stress dramatically strengthens the sueprconductivity, with Tc more than doubling, by driving one of the Fermi surfaces through a Van Hove singularity in the density of states. The superconductivity of YBa2Cu3O6+x, on the other hand, is suppressed by uniaxial stress. Through inelastic X-ray scattering measurements on near-1/8-doped YBa2Cu3O6+x, we show that stress applied along the a axis can induce long-range charge density wave order, and that this order and the superconductivity compete strongly.
Host: Bill Halperin
Yas Shemirani
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