Spin susceptibility of Anderson impurities in arbitrary conduction bands

Spin susceptibility of Anderson impurities is a key quantity in understanding the physics of Kondo screening. Traditional numerical renormalization group (NRG) calculation of the impurity contribution $\chi_{\textrm{imp}}$ to susceptibility, defined originally by Wilson in a flat wide band, has been generalized before to structured conduction bands. The results brought about non-Fermi-liquid and diamagnetic Kondo behaviors in $\chi_{\textrm{imp}}$, even when the bands are not gapped at the Fermi energy. Here, we use the full density-matrix (FDM) NRG to present high-quality data for the local susceptibility $\chi_{\textrm{loc}}$ and to compare them with $\chi_{\textrm{imp}}$ obtained by the traditional NRG. Our results indicate that those exotic behaviors observed in $\chi_{\textrm{imp}}$ are unphysical. Instead, the low-energy excitations of the impurity in arbitrary bands only without gap at the Fermi energy are still a Fermi liquid and paramagnetic. We also demonstrate that unlike the traditional NRG yielding $\chi_{\textrm{loc}}$ less accurate than $\chi_{\textrm{imp}}$, the FDM method allows a high-precision dynamical calculation of $\chi_{\textrm{loc}}$ at much reduced computational cost, with an accuracy at least one order higher than $\chi_{\textrm{imp}}$. Moreover, artifacts in the FDM algorithm to $\chi_{\textrm{imp}}$, and origins of the spurious non-Fermi-liquid and diamagnetic features are clarified. Our work provides an efficient high-precision algorithm to calculate the spin susceptibility of impurity for arbitrary structured bands, while negating the applicability of Wilson's definition to such cases.Comment: the published versio

Opinion dynamics on directed small-world networks

In this paper, we investigate the self-affirmation effect on formation of public opinion in a directed small-world social network. The system presents a non-equilibrium phase transition from a consensus state to a disordered state with coexistence of opinions. The dynamical behaviors are very sensitive to the density of long-range interactions and the strength of self-affirmation. When the long-range interactions are sparse and individual generally does not insist on his/her opinion, the system will display a continuous phase transition, in the opposite case with high self-affirmation strength and dense long-range interactions, the system does not display a phase transition. Between those two extreme cases, the system undergoes a discontinuous phase transition.Comment: 6 pages, 5 figure

Determination of Anthraquinone Content in Lac Dye Through Combined Spectrophotometry and HPCE

AbstractThis study is aim to establish the method for determination of anthraquinone content in lac dye with the combined spectrophotometry and HPCE, With the 0.5%Mg(Ac)2-CH3OH solution as the colour-developing agent, the carminic acid concentration within the concentration of 5∼50μg/mL presents a good linear relationship with the absorbance under the wavelength of 540nm (R=0.9994). Through the test, the results showed that the total anthraquinone content in lac dye was 82.13%, average recovery rate 97.80%, RSD 1.31%. Under 291nm detection wavelength and 25°C column temperature, with pH8.035 60mmol/LNa2HPO4-Na2B4O7 • 10H2O mixed buffer as background electrolyte and 60cm × 75μm uncoated capillary column as separation lanes, separation voltage 20kV, pressure 0.5psi × 10s for sample injection, the relative contents of five components laccaic acids A, B, C, D, E were measured by peak area normalization method; combined with the spectrophotometry, the contents of five anthraquinone components - laccaic acids A, B, C, D, E were determined, respectively 40.42%, 17.66%, 2.54%, 1.51%, 20.00%

Fabrication and Characterization of Composite Containing HCl-Doped Polyaniline and Fe Nanoparticles

HCl-doped polyaniline powder (HCl-PANI) was synthesized by using a polymerization procedure. Fe nanoparticles were then deposited on the HCl-PANI at room temperature by direct current magnetron sputtering. After this process the HCl-PANI-Fe composite was obtained. Fe nanoparticle size in the composite is about 100 nm. HCl-PANI structure is not influenced by the Fe nanoparticles. The composite pellet has room temperature ferromagnetism and a conductivity of 0.25 S/cm. Temperature dependence of the conductivity reveals that a carrier transport mechanism in the composite is three-dimensional variable range hopping. Thermogravimetric analysis reveals that a weight loss of the HCl-PANI-Fe composite is smaller than that of the HCl-PANI for the same heating temperature when the temperature exceeds 230°C

Scalable fabrication of high-quality crystalline and stable FAPbI(3) thin films by combining doctor-blade coating and the cation exchange reaction

Formamidinium lead iodide (FAPbI(3)) is one of the most extensively studied perovskite materials due to its narrow band gap and high absorption coefficient, which makes it highly suitable for optoelectronic applications. Deposition of a solution containing lead iodide (PbI2) and formamidinium iodide (FAI) or sequential deposition of PbI2 and FAI usually leads to the formation of films with a poor morphology and an unstable crystal structure that readily crystallize into two different polymorphs: the photoinactive yellow phase and the photoactive black phase. In this work, 2D 2-phenylethylammonium lead iodide (PEA(2)PbI(4)) thin films are deposited by a scalable doctor-blade coating technique and used as a growth template for the high-quality 3D FAPbI(3) perovskite thin films which are obtained by organic cation exchange. We report the structural, morphological and optical properties of these converted 3D FAPbI(3) perovskite films which we compare to the directly deposited 3D FAPbI(3) films. The converted FAPbI(3) thin films are compact, smooth, and highly oriented and exhibit better structural stability in comparison with the directly deposited 3D films. These results not only underscore the importance of the employed deposition techniques in fabricating highly crystalline and stable perovskite thin films but also provide a strategy to easily obtain very compact perovskite layers using doctor-blade coating