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441.
Observation of a Ubiquitous(π,π)-Type Nematic Superconducting Order in the Whole Superconducting Dome of Ultra-Thin BaFe_(2-x)Ni_xAs_2 Single Crystals 下载免费PDF全文
Yu Dong Yangyang Lv Zuyu Xu M.Abdel-Hafiez A.N.Vasiliev Haipeng Zhu Junfeng Wang Liang Li Wanghao Tian Wei Chen Song Bao Jinghui Wang Yueshen Wu Yulong Huang Shiliang Li Jie Yuan Kui Jin Labao Zhang Huabing Wang Shun-Li Yu Jinsheng Wen Jian-Xin Li Jun Li Peiheng Wu 《中国物理快报》2021,(9):116-126
In iron-based superconductors,the(0,π) or(π,0) nematicity,which describes an electronic anisotropy with a fourfold symmetry breaking,is well established and believed to be important for understanding the superconducting mechanism.However,how exactly such a nematic order observed in the normal state can be related to the superconducting pairing is still elusive.Here,by performing angular-dependent in-plane magnetoresistivity using ultra-thin flakes in the steep superconducting transition region,we unveil a nematic superconducting order along the(π,π) direction in electron-doped BaFe_(2-x)Ni_xAs_2 from under-doped to heavily overdoped regimes with x=0.065-0.18.It shows superconducting gap maxima along the(π,π) direction rotated by 45° from the nematicity along(0,π) or(π,0) direction observed in the normal state.A similar(π,π)-type nematicity is also observed in the under-doped and optimally doped hole-type Ba_(1-y)K_yFe_2 As_2,with y=0.2-0.5.These results suggest that the(π,π) nematic superconducting order is a universal feature that needs to be taken into account in the superconducting pairing mechanism in iron-based superconductors. 相似文献
442.
Jinghui Liu Changfeng Ma 《计算数学(英文版)》2014,(4):476-490
Based on the nonmonotone line search technique proposed by Gu and Mo (Appl. Math. Comput. 55, (2008) pp. 2158-2172), a new nonmonotone trust region algorithm is proposed for solving unconstrained optimization problems in this paper. The new algorithm is developed by resetting the ratio ρk for evaluating the trial step dk whenever acceptable. The global and superlinear convergence of the algorithm are proved under suitable conditions. Numerical results show that the new algorithm is effective for solving unconstrained optimization problems. 相似文献
443.
By using the properties of w-distances and Gerstewitz’s functions,we first give a vectorial Takahashi’s nonconvex minimization theorem with a w-distance.From this,we deduce a general vectorial Ekeland’s variational principle,where the objective function is from a complete metric space into a pre-ordered topological vector space and the perturbation contains a w-distance and a non-decreasing function of the objective function value.From the general vectorial variational principle,we deduce a vectorial Caristi’s fixed point theorem with a w-distance.Finally we show that the above three theorems are equivalent to each other.The related known results are generalized and improved.In particular,some conditions in the theorems of [Y.Araya,Ekeland’s variational principle and its equivalent theorems in vector optimization,J.Math.Anal.Appl.346(2008),9-16] are weakened or even completely relieved. 相似文献
444.
Journal of Statistical Physics - The basic $$kappa $$-color box-ball (BBS) system is an integrable cellular automaton on one dimensional lattice whose local states take $${0,1,ldots ,kappa }$$... 相似文献
445.
For a convex set-valued map between p-normed (0 < p ≤ 1) spaces, we give a criterion for its inverse to be locally Lipschitz of order p. From this we obtain the Robinson-Ursescu Theorem in p-normed spaces and the open mapping and closed graph theorems for closed convex set-valued maps. 相似文献
446.
LI Jinghui PENG Jiangde JIANG Xin YAO Minyu WU Gengsheng FAN Chongcheng ZHOU Bingkun 《Chinese Journal of Lasers》1994,3(1):21-25
A0.98μmLaserDiodePumpedErbium-DopedFiberAmplifierwith40nmBandwidth¥LIJinghui;PENGJiangde;JIANGXin;YAOMinyu;WUGengsheng;FANCho... 相似文献
447.
The magneto-reflectance of ferrimagnetic CoCr2S4 has been measured in the visible and near infrared. A very large magneto-dispersion is observed at about 600 cm?1, which can be associated with crystal field transitions of divalent cobalt. 相似文献
448.
Self assembly of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) followed by reactive ion etching technique is a promising method for fabricating periodical silica nanopatterns and can be applicable for device fabrication on nanoscale. We demonstrated a technologically useful way to control the inorganic silica nanostructures in thin films by directly mixing asymmetric (PS-b-PDMS) diblock copolymer with homopolymers of majority component, polystyrene (PS) under solvent vapor annealing followed by UV/O3 treatment. The effects of molecular weight and volume fraction of added homopolymer (PS) on morphology and size of the nanostructure of blends have been carefully investigated by atomic force microscopy. Different morphology transitions observed on the ordering film surface by atomic force microscopy (AFM) are associated with kinetics of phase evolution with respect to homo-PS with different molecular weight. The periodic spacings and dimensions of the microdomains were readily tuned at the same time, just by adjusting the molecular weight and volume fraction of the blended homopolymer. 相似文献
449.
Jian‐Kuan Wu Lian‐Ming Lyu Ching‐Wen Liao Yu‐Ning Wang Prof. Michael H. Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(45):14473-14478
In this study, we have developed for the first time a fast and energy‐efficient method for the synthesis of PbS nanocrystals with systematic shape evolution from cubic to truncated cubic, cuboctahedral, truncated octahedral, and octahedral structures. The method involves the addition of a small volume of preheated lead acetate and thioacetamide (TAA) mixture to an aqueous growth solution of lead acetate, thioacetamide, cetyltrimethylammonium bromide, and nitric acid. By varying the amount of thioacetamide added to the growth solution, PbS nanocrystals with different morphologies were generated in 2 h at 90 °C. Slight experimental modifications were adopted to generate truncated octahedra. The nanocrystals have very uniform dimensions with average sizes of 32–47 nm. Their structures have been extensively examined by electron microscopy. Nanocube sizes can also be tuned within a range. UV/Vis absorption spectra of PbS cubes, cuboctahedra, and octahedra all show decreasing but continuous absorption from 300 nm to beyond 1000 nm. By monitoring the speed of darkening of solution color, particle growth rate was found to be fastest for nanocubes, followed by truncated cubes, cuboctahedra, and octahedra. These monodisperse nanocrystals can readily form self‐assembled structures. Truncated cubes and octahedra that form monolayer and multilayer packing arrangements have also been studied. This green approach to the synthesis of PbS nanocrystals with fine size and shape control should allow for investigations of their facet‐dependent properties and the fabrication of novel heterostructures. 相似文献
450.
Li Zhou Peiying Cai Yan Feng Jinghui Cheng Haifeng Xiang Jin Liu Di Wu Xiangge Zhou 《Analytica chimica acta》2012
A series of water-soluble sulfonato-Salen-type ligands derived from different diamines including 1,2-ethylenediamine (Et-1–Et-4), 1,2-cyclohexanediamine (Cy-1 and Cy-2), 1,2-phenylenediamine (Ph-1–Ph-3 and PhMe-1–PhMe-4), and dicyano-1,2-ethenediamine (CN-1) has been designed and prepared. Sulfonate groups of ligands ensure good stability and solubility in water without affecting their excited state properties. These ligands exhibit strong UV/Vis-absorption and blue, green, or orange fluorescence. Time-dependent-density functional theory calculations have been undertaken to reveal the influence of ligand nature, especially sulfonate groups, on the frontier molecular orbitals. Since their fluorescence is selectively quenched by Cu2+, the sulfonato-Salen-type ligands can be used as highly selective and sensitive turn-off fluorescence sensors for the detection of Cu2+ in water and fluorescence imaging in living cells. 相似文献