SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 37: Ruthenates
TT 37.11: Talk
Wednesday, March 29, 2023, 17:45–18:00, HSZ 201
Tuning van Hove singularities in strontium ruthenate with isovalent Barium doping — •Caitlin I O’Neil1,2, Maximillian T Pelly1,2, Ben Gade1, Alexandra S Gibbs1,3,4, and Andreas W Rost1,2 — 1SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK — 2MPI for Chemical Physics of Solids, Dresden, Germany — 3MPI for Solid State Research, Stuttgart, Germany — 4ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, UK
Controlling a van Hove singularity (VHS) close the Fermi energy (EF) of a compound allows control of the low temperature phases as shown for example in recent experiments in single layer ruthenates [1,2]. This study pursues a new direction of structural doping of Sr3Ru2O7 by the substitution of barium onto the strontium site. Powder samples of (Sr1−xBax)3Ru2O7 were synthesised from x=0.0 - 0.12. The samples were analysed with X-ray and neutron diffraction, magnetic susceptibility and heat capacity measurements. The unit cell volume changes linearly with doping with the primary structural change being an adjustment of the RuO6 octahedral rotation mode magnitude. Using heat capacity we map the evolution of the VHS towards the EF, crossing it at x=0.08. Intriguingly, heat capacity shows that the strength of the singularity is decreased, contrary to standard scenarios. In combination with DFT calculations we trace this back to the primary role of the rotation mode in controlling the VHS in ruthenates.
[1] Y.-S. Lie et al., Nature 607, 276 (2022)
[2] C. A. Marques et al., Adv. Mater. 33, e21005