Collective properties of eutectic ruthenates: Role of nanometric inclusions

We study the modification of the electronic structure induced by nanometric inclusions of Sr₂RuO₄ embedded as c-axis stacking fault in Sr₃Ru₂O₇ and vice versa. The change of the density of states near the Fermi level is investigated as a function of the electron density, the strength of the charge transfer at the interfaces between the inclusion and the host, and of the distance from the inclusion. Then, we examine how the tendency toward long-range orders is affected by the presence of the nanometric inclusions. This is done by looking at the basic criteria for broken symmetry states such as superconductivity, ferromagnetism, and metamagnetism. We show that, according to the strength of the charge transfer coupling, the ordered phases may be enhanced or hindered, as a consequence of the interplay between the host and the inclusion, and we clarify the role played by the orbital degree of freedom showing an orbital selective behavior within the t2g bands. A discussion on the connections between the theoretical outcome and the experimental observations is also presented.