Berlin 2018 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

TT: Fachverband Tiefe Temperaturen

TT 16: Superconductivity: Properties and Electronic Structure II

TT 16.1: Talk

Monday, March 12, 2018, 15:00–15:15, H 0110

Resistivity in the Vicinity of a Van Hove Singularity: Sr₂RuO₄ Under Uniaxial Pressure — •Mark E. Barber^1,2, Alexandra S. Gibbs^2,3, Yoshiteru Maeno⁴, Andrew P. Mackenzie^1,2, and Clifford W. Hicks¹ — ¹Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — ²Scottish Universities Physics Alliance (SUPA), University of St. Andrews, United Kingdom — ³ISIS Facility, Rutherford Appleton Laboratory, United Kingdom — ⁴Department of Physics, Kyoto University, Japan

Sr₂RuO₄ is an unconventional superconductor with a well characterised Fermi liquid normal state. One of its three conduction bands is known to be in close proximity to a Van Hove singularity. We have previously shown that the application of uniaxial pressure causes T_c to pass through a strong peak at a uniaxial compression of 0.6 %, and at which T_c is more than double its value in the unstrained lattice. DFT calculations provide strong evidence that this peak coincides with tuning the Van Hove singularity to the Fermi level. Here, we present data on the normal-state resistivity as Sr₂RuO₄ is tuned through this peak and analyse the temperature dependence, which also appears to be consistent with a Van Hove singularity. In particular, the low-temperature resistivity also passes through a pronounced peak - arguably a surprise because the singularity affects only small sections of one Fermi surface - and at the peak its temperature dependence deviates strongly from the Fermi liquid T² dependence.