Analysis of Charge-spin-orbital Fluctuations by Ab Initio Calculation and Random Phase Approximation: Application to Non-coplanar Antiferromagnet Cd2Os2O7

We present a systematic analysis on the basis of ab initio calculations and many-body perturbation theory for clarifying the dominant fluctuation in complex charge-spin-orbital coupled systems. For a tight-binding multiband model obtained from the maximally-localized Wannier function analysis of the band structure by the local density approximation, we take into account electron correlations at the level of random phase approximation. To identify the dominant fluctuation, we carry out the eigenmode analysis of the generalized susceptibility that includes all the multiple degrees of freedom: charge, spin, and orbital. We apply this method to the paramagnetic metallic phase of a pyrochlore oxide Cd$_2$Os$_2$O$_7$, which shows a metal-insulator transition accompanied by a peculiar noncoplanar antiferromagnetic order of all-in all-out type. We find that the corresponding spin fluctuation is dominantly enhanced by the on-site Coulomb repulsions in the presence of strong spin-orbit coupling and trigonal crystal field splitting. Our results indicate that the combined method offers an effective tool for the systematic analysis of potential instabilities in strongly correlated electron materials.Comment: 8 pages, 4 figure

Charge-spin-orbital fluctuations in mixed valence spinels: Comparative study of AlV2O4{\mathrm{AlV}}_{2}{\mathrm{O}}_{4} and LiV2O4{\mathrm{LiV}}_{2}{\mathrm{O}}_{4}

Mixed valence spinels provide a fertile playground for the interplay between charge, spin, and orbital degrees of freedom in strongly correlated electrons on a geometrically frustrated lattice. Among them, AlV2O4 and LiV2O4 exhibit contrasting and puzzling behavior: self-organization of seven-site clusters and heavy fermion behavior. We theoretically perform a comparative study of charge-spin-orbital fluctuations in these two compounds, on the basis of the multiband Hubbard models constructed by using the maximally localized Wannier functions obtained from the ab initio band calculations. Performing the eigenmode analysis of the generalized susceptibility, we find that, in AlV2O4, the relevant fluctuation appears in the charge sector in σ-bonding type orbitals. In contrast, in LiV2O4, optical-type spin fluctuations in the a1g orbital are enhanced at an incommensurate wave number at low temperature. Implications from the comparative study are discussed for the contrasting behavior, including the metal-insulator transition under pressure in LiV2O4

Associations between lipid profiles and MACE in hemodialysis patients with percutaneous coronary intervention: From the FU-Registry

AbstractBackgroundIt is well known that percutaneous coronary intervention (PCI) in hemodialysis (HD) patients is associated with higher rates of in-stent restenosis and major adverse cardiovascular events (MACE) compared to that in non-HD patients, even if the target value in cholesterol management is achieved.MethodsTo evaluate the factors that are associated with MACE in HD patients, we selected 142 HD patients (164 lesions) without acute coronary syndrome (ACS) from 2148 patients (2568 lesions) who underwent PCI in our database of the FU-Registry [UMIN000005679, Fukuoka University Hospital EC/IRB:10-1-08(09-105)], and compared 52 patients (53 lesions) with MACE [MACE(+)] to 90 patients (111 lesions) without MACE [MACE(−)].ResultsTotal cholesterol (TC: 150±30mg/dL vs 166±39mg/dL, p<0.05) and high-density lipoprotein cholesterol (HDL-C: 40.1±14.7mg/dL vs 47.8±13.5mg/dL, p<0.01) levels were significantly lower in the MACE(+) group at follow-up. No significant differences were observed in other parameters, including triglyceride, low-density lipoprotein cholesterol (LDL-C; LDL-C/HDL-C ratio, and % changes in HDL-C, non-HDL-C, LDL-C), and hemoglobin A1c (US National Glycohemoglobin Standardization Program) between before and after PCI. TC, LDL-C, and non-HDL-C at the time of PCI and TC, and HDL-C at the 9-month follow-up were negatively correlated with MACE, while body mass index (BMI) [odds ratio (OR): 0.81; 95% confidence interval (CI): 0.68–0.95)], prior coronary artery bypass graft (CABG) (OR: 3.89; 95%CI: 1.29–12.6), and insulin use (OR: 3.17; 95%CI: 1.23–8.55) were strongly correlated with MACE in a multivariate analysis.ConclusionBMI, CABG, and insulin use, but not LDL-C, are independent predictors of MACE in HD patients, suggesting that the application of lipid management for non-HD patients to HD patients at the time of PCI may not necessarily be beneficial for medium-term clinical outcomes