Model for the magnetic order and pairing channels in Fe pnictide superconductors.

Electronic dispersion anomalies in iron pnictide superconductors.

Recently, experimental studies of the spin excitation spectrum revealed a strong temperature dependence in the normal state and a resonance feature in the superconducting state of several Fe-based superconductors. Based on these findings, we develop a model of electrons interacting with a temperature dependent magnetic excitation spectrum and apply it to angle resolved photoemission in Ba(1-x)K...

Anisotropy of electrical transport in pnictide superconductors studied using Monte Carlo simulations of the spin-fermion model.

An undoped three-orbital spin-fermion model for the Fe-based superconductors is studied via Monte Carlo techniques in two-dimensional clusters. At low temperatures, the magnetic and one-particle spectral properties are in agreement with neutron and photoemission experiments. Our main results are the resistance versus temperature curves that display the same features observed in BaFe(2)As(2) det...

Competing pairing symmetries in a generalized two-orbital model for the pnictide superconductors.

We introduce and study an extended "t-U-J" two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms explicitly allows us to enhance the strength of the (π,0)-(0,π) spin order which favors the presence of tightly bound pairing states even in the small clusters that are here exactly diagonalized. The A(1g) and B(2g) pai...

Role of Covalent Fe-As Bonding in the Magnetic Moment Formation and Exchange Mechanisms in Iron-Pnictide Superconductors

Persistent high-energy spin excitations in iron-pnictide superconductors.

Motivated by the premise that superconductivity in iron-based superconductors is unconventional and mediated by spin fluctuations, an intense research effort has been focused on characterizing the spin-excitation spectrum in the magnetically ordered parent phases of the Fe pnictides and chalcogenides. For these undoped materials, it is well established that the spin-excitation spectrum consists...