Dresden 2020 – wissenschaftliches Programm
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TT 41.4: Vortrag
Mittwoch, 18. März 2020, 16:00–16:15, HSZ 201
Nematicity and checkerboard order in the surface layer of Sr2RuO4 — •Carolina A. Marques1, Luke C. Rhodes1, Veronica Granata2, Rosalba Fittipaldi2, Antonio Vecchione2, Andreas W. Rost1, and Peter Wahl1 — 1SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, United Kingdom — 2CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, Fisciano, I-84084, Italy.
Superconductivity in strongly correlated systems is often found near exotic electronic phases, such as antiferromagnetism and electronic nematicity. These phases can be highly sensitive to minor changes in the crystal structure, induced by doping or strain. In the unconventional superconductor Sr2RuO4, a 6∘ rotation of the RuO6 octahedra at the surface seems to suppress its superconducting state and, additionally, pushes a van Hove singularity below the Fermi energy.
Using ultra-low temperature Scanning tunnelling microscopy (STM), we study the low energy electronic properties of the reconstructed surface of Sr2RuO4. Our measurements show clear signatures of C4 symmetry breaking, together with the appearance of a checkerboard order. This order is associated with a peak in the tunnelling spectrum, which splits in a magnetic field, revealing a charge nature. Tight binding calculations show that a nematic order parameter coexisting with a modulation of the charge-density reproduces the observed low energy density of states. Understanding the underlying physics at this surface provides a new platform to study the strongly correlated phases of Ruthenate materials.