Search

We report temperature-dependent transport and x-ray diffraction measurementsof the influence of Ti hole doping on the charge density wave (CDW) in1T-Ta(1-x)Ti(x)S(2). Confirming past studies, we find that even traceimpurities eliminate the low-temperature commensurate (C) phase in this system.Surprisingly, the magnitude of the in-plane component of the CDW wave vector inthe nearly commensurate (NC) phase does not change significantly with Ticoncentration, as might be expected from a changing Fermi surface volume.Instead, the angle of the CDW in the basal plane rotates, from 11.9 deg at x=0to 16.4 deg at x=0.12. Ti substitution also leads to an extended region ofcoexistence between incommensurate (IC) and NC phases, indicating heterogeneousnucleation near the transition. Finally, we explain a resistive anomalyoriginally observed by DiSalvo [F. J. DiSalvo, et al., Phys. Rev. B {\bf 12},2220 (1975)] as arising from pinning of the CDW on the crystal lattice. Ourstudy highlights the importance of commensuration effects in the NC phase,particularly at x ~ 0.08.

Charge density waves (CDWs) have been observed in nearly all families of copper-oxide superconductors. But the behavior of these phases across different families has been perplexing. In La-based cuprates, the CDW wavevector is an increasing function of doping, exhibiting the so-called Yamada behavior, while in Y- and Bi-based materials the behavior is the opposite. Here, we report a combined resonant soft X-ray scattering (RSXS) and neutron scattering study of charge and spin density waves in isotopically enriched La1.8−xEu0.2SrxCuO4 over a range of doping 0.07≤x≤0.20. We find that the CDW amplitude is temperature independent and develops well above experimentally accessible temperatures. Further, the CDW wavevector shows a nonmonotonic temperature dependence, exhibiting Yamada behavior at low temperature with a sudden change occurring near the spin ordering temperature. We describe these observations using a Landau–Ginzburg theory for an incommensurate CDW in a metallic system with a finite charge compressibility and spin-CDW coupling. Extrapolating to high temperature, where the CDW amplitude is small and spin order is absent, our analysis predicts a decreasing wavevector with doping, similar to Y and Bi cuprates. Our study suggests that CDW order in all families of cuprates forms by a common mechanism.

Introduction: There are few studies integrating the common causes of osteoporosis and obesity (disorders of body composition). A first step is to investigate correlations between their biological phenotypes to determine their common integrative physiology., Objective: To correlate the variation of bone mineral density with phenotypes of body composition and biomarkers of bone physiology, insulin-glucose axis, and adipose tissue., Methods: Cross-sectional study of 75 women (aged 18-45 years)., Measurements: Body mass index, waist, fat mass, lean mass (dual-energy X-ray absorptiometry), glucose, insulin, osteocalcin, leptin, tumor necrosis factor alpha., Statistical Analysis: multivariate general linear model, SPSS v.22, p<0.05., Results: Age: 32.08±7.33. Bone mineral content multivariate general linear model 1 with two phenotypes excluded (glucose, insulin): osteocalcin (β=-0.228, p=0.011), lean mass (β=0.606, p=0.001) and fat mass (β=1.237, p=0.001) in 62.0%. The bone mineral density multivariate general linear model 2 with three phenotypes excluded (body mass index, glucose, tumor necrosis factor alpha): insulin (β=0.250, p=0.024), osteocalcin (β=-0.362, p=0.001), lean mass (β=0.512, p=0.001) and fat mass (β=0.701, p=0.001) in 46.3%., Conclusions: Results show that body composition with an increased lean mass is beneficial to bone. This study reaffirms the importance of performing regular exercise to prevent muscle loss.