Quantifying electronic correlation strength in a complex oxide: A combined DMFT and ARPES study ofLaNiO3

Abstract

The electronic correlation strength is a basic quantity that characterizes the physical properties of materials such as transition metal oxides. Determining correlation strengths requires both precise definitions and a careful comparison between experiment and theory. In this paper, we define the correlation strength via the magnitude of the electron self-energy near the Fermi level. For the case of LaNiO 3 , we obtain both the experimental and theoretical mass enhancements m /m by considering high resolution angle-resolved photoemission spectroscopy (ARPES) measurements and density functional + dynamical mean field theory (DFT + DMFT) calculations. We use valence-band photoemission data to constrain the free parameters in the theory and demonstrate a quantitative agreement between the experiment and theory when both the realistic crystal structure and strong electronic correlations are taken into account. In addition, by considering DFT + DMFT calculations on epitaxially strained LaNiO 3 , we find a strain-induced evolution of m /m in qualitative agreement with trends derived from optics experiments. These results provide a benchmark for the accuracy of the DFT + DMFT theoretical approach, and can serve as a test case when considering other complex materials. By establishing the level of accuracy of the theory, this work also will enable better quantitative predictions when engineering new emergent properties in nickelate heterostructures.

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

“…Furthermore, the measured occupied bandwidth throughout the Brillouin zone is within ten percent of the DFT values at bind- ing energies extending to larger than 1 eV. This level of quantitative agreement between experiment and DFT is remarkable in transition metal oxides, where typically m * /m DF T ≈ 2 − 6, in material families such as cuprates, nickelates, manganites, titanates, ruthenates, and other iridates [29][30][31][32][33][34] . From EDC fits of the QP peak, we extract an effective quasiparticle residue of Z ′ = 0.9 ± 0.1 (Supplemental), in good agreement with the lack of appreciable velocity renormalization.…”

Breathing distortions in the metallic, antiferromagnetic phase of LaNiO$_3$

“…Another striking feature of Guo et al's measurments is the large value of 17 mJ mol −1 K −2 obtained for the Sommerfeld coefficient γ, which is around five times larger than the value calculated here for the disproportionated antiferromagnetic phases. Previous ARPES [44,[64][65][66], optical conductivity [28,67,68], and thermodynamics measurements [61] have also identified large electron mass enhancement and possible formation of pseudogapped state in LaNiO 3 , and this has been discussed in terms of strong local electronic correlations. When the values for the on-site Coulomb U and Hund's rule J are used such that they reproduce the experimentally measured electronic structure, DMFT calculations can explain such an enhancement [44,66].…”

“…Previous ARPES [44,[64][65][66], optical conductivity [28,67,68], and thermodynamics measurements [61] have also identified large electron mass enhancement and possible formation of pseudogapped state in LaNiO 3 , and this has been discussed in terms of strong local electronic correlations. When the values for the on-site Coulomb U and Hund's rule J are used such that they reproduce the experimentally measured electronic structure, DMFT calculations can explain such an enhancement [44,66]. The calculations presented here show that different structural phases occur close in energy in both the nonmagnetic and antiferromagnetic LaNiO 3 , and the nonlocal fluctuations between these structures might provide an additional avenue for the enhancement.…”

Electronic structure of buried LaNiO3 layers in (111)-oriented LaNiO3/LaMnO3 superlattices probed by soft x-ray ARPES

“…A similar bandwidth was observed for thin films grown along the (001) direction indicating that distortions imposed by the substrate do not play a major part in determining this parameter. 43 We then turn our attention to the k-space cut through the R point at the BZ corner. In this measurement shown in Fig.…”