SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 19: Unconventional Superconductors
TT 19.5: Talk
Thursday, September 30, 2021, 12:15–12:30, H6
Nematicity and checkerboard order in the surface layer of Sr2RuO4 — •Carolina A. Marques1, Luke C. Rhodes1, Rosalba Fittipaldi2, Veronica Granata3, Chi Ming Yim1, Renato Buzio2, Andrea Gerbi2, Antonio Vecchione2, Andreas W. Rost1,4, and Peter Wahl1 — 1SUPA, School of Physics and Astronomy, University of St Andrews, UK. — 2CNR-SPIN, Italy. — 3Dipartimento di Fisica, Università di Salerno, Italy. — 4Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
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 pushes a van Hove singularity below the Fermi energy. Using ultra-low temperature Scanning tunnelling microscopy, we study the low energy electronic properties of the reconstructed surface of Sr2RuO4[1]. Our measurements show clear signatures of C4 symmetry breaking, together with the appearance of a checkerboard order, 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 charge modulation 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.
[1] Adv. Mat. 2100593 (2021)