Investigation of superconductivity and metamagnetism in single and double layered ruthenates using angle resolved photoelectron spectroscopy

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Single- and double-layered ruthenates belong to the most prominent examples, where competition of multiple interactions leads to emergence of novel ordered phases of electronic matter. In particular, the former is the first unconventional p-wave superconductor, while the latter is famous for its proximity to quantum critical point and metamagnetism. Moreover, upon Ca substitution these materials can be driven into an antiferromagnetic Mott insulator state. Despite unceasing theoretical and experimental interest to these materials a convergent picture that would explain such a variety of complex ground states and their interrelation starting from a quasiparticle band structure picture is still missing. The aim of this project is to clarify the electronic structure of single- and double-layer ruthenates in the whole accessible range of chemical doping and temperatures using angle resolved photoelectron spectroscopy—an experimental technique providing a complete set of information on the k-resolved band structure. While momentum and band resolved data on superconducting gap in Sr2RuO4 would help to limit the number of theoretical approaches currently suggested to account for the occurrence of superconductivity in this material, a detailed investigation of chemical doping should provide the most direct experimental demonstration for the evolution of itinerant paramagnet phase into antiferromagnetic one. The latter is necessary to understand to which extent the selective Mott transition and orbital ordering are apt descriptions, when speaking of complex ordering phenomena observed in ruthenates.