Spin-orbit and anisotropic strain effects on the electronic correlations of Sr2RuO4

V. L. VILDOSOLA

Bariloche

Workshop; SLAFES XXIII; 2018

Sr 2 RuO 4 is isostructural with the cuprate parent compound La 2 CuO 4 . Since the discovery of the supercon-ductivity in Sr 2 RuO 4 bellow T c =1.5 K, it has become a key material in the field of strongly correlated systemsbecause, at variance with the Mott insulator character of La 2 CuO 4 , it exhibits very exotic metallic properties inthe normal phase. In view of the subtle interplay between crystal structure, oxygen-transition metal hybridization,multi-orbital Coulomb interactions and spin-orbit coupling, many experimental and theoretical investigations havebeen carried out in order to give insight and understanding of the peculiar physical properties of this compound.The possibility of controlling the electronic properties of Sr 2 RuO 4 by applying external strain has been recentlyaddressed experimentally. It has been shown that the evolution of the superconducting T c with uniaxial strainpresents a peak that seems to be correlated with a Lifshitz transition of the xy-Ru band [1]. This transitionassociated to the shift of a Van Hove singularity has also been observed in systems under biaxial strain [2]. Aninteresting open question is to what extent this Lifshitz transition affects the electronic correlations in the normalphase of Sr 2 RuO 4 . We implement and apply an LDA+DMFT approach using the rotationally invariant slave bosontechnique as impurity solver, to study the electronic correlations of Sr 2 RuO 4 in the presence of anisotropic strainand spin-orbit coupling. We find that the spin-orbit coupling plays a crutial role in the mass enhancement differ-entiation between the Fermi surface quasi one-dimensional α and β bands, and on its momentum dependence.The mass enhancement, however, is only weakly affected by either uniaxial and biaxial strain, even accross theLifshitz transition induced thereby.[1] A. Steppke et al., Science, 355, eaaf9398 (2017).[2] B. Burganov et al., Physical Review Letters, 116, 197003 (2016).