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The new discovered iron-based superconductors have chain-like As layers. These layers generate an additional 3-dimensional hole pocket and cone-like electron pockets. The former is attributed to the Ca d and As1 pz orbitals and the latter are attributed to the anisotropic Dirac cone, contributed by As1 px and py orbitals. We find that large gaps on these pockets open in the collinear antiferromagnetic ground state of CaFeAs2, suggesting that the chain-like As layers are strongly coupled to FeAs layers. Moreover due to the low symmetry crystal induced by the As layers, the bands attributed to FeAs layers in ky = π plane are two-fold degenerate but in kx = π plane are lifted. This degeneracy is protected by a hidden symmetryΥ =TRy. Ignoring the electron cones, the materials can be well described by a six-band model, including five Fe d and As1 pz orbitals. We suggest that these new features may help us to identify the sign change and pairing symmetry in iron based superconductors.

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We investigate the pairing symmetry of layered BiS2 compounds by assuming that electronelectron correlation is still important so that the pairing is rather short range. We find that the extended s-wave pairing symmetry always wins over d-wave when the pairing is confined between two short range sites up to next nearest neighbors. The pairing strength is peaked around the doping level x = 0.5, which is consistent with experimental observation. The extended s-wave pairing symmetry is very robust against spin-orbital coupling because it is mainly determined by the structure of Fermi surfaces. Moreover, the extended s-wave pairing can be distinguished from conventional s-wave pairing by measuring and comparing superconducting gaps of different Fermi surfaces.

Recent angle-resolved photoemission spectroscopy (ARPES) experiments have suggested that BiS2-based superconductors are at very low electron doping. Using random phase approximation (RPA) and functional renormalization group (FRG) methods, we find that g-wave pairing symmetry belonging to the A2g irreducible representation is dominant at electron doping x < 0.25. The pairing symmetry is determined by inter-pocket nesting and orbital characters on the Fermi surfaces and is robust in a two-orbital model including both Hund's coupling J, and Hubbard-like Coulomb interactions U and U with relatively small J (J ≤ 0.2U ). With the increasing electron doping, the g-wave state competes with both the s-wave A1g and d-wave B2g states and no pairing symmetry emerges dominantly.

We predict that CaFeAs2, a newly discovered iron-based high temperature (Tc) superconductor, is a staggered intercalation compound that integrates topological quantum spin hall (QSH) and superconductivity (SC). CaFeAs2 has a structure with staggered CaAs and FeAs layers. While the FeAs layers are known to be responsible for high Tc superconductivity, we show that with spin orbital coupling each CaAs layer is a Z2 topologically nontrivial two-dimensional QSH insulator and the bulk is a 3-dimensional weak topological insulator. In the superconducting state, the edge states in the CaAs layer are natural 1D topological superconductors. The staggered intercalation of QSH and SC provides us an unique opportunity to realize and explore novel physics, such as Majorana modes and Majorana Fermions chains.

Supramolecular structure of jackfruit seed starch and its relationship with digestibility and physicochemical properties.Carbohydrate Polymers http://dx.doi.org/10. 1016/j.carbpol.2016.05.030 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.