相关论文: Orbital order from the on-site orbital attraction

Pairing symmetries of iron-based superconductors are investigated systematically in a five-orbital model within the different regions of interaction parameters by functional renormalization group(FRG). Even for a fixed Fermi surface with…

The lifting of $d_{xz}$-$d_{yz}$ orbital degeneracy is often considered a hallmark of the nematic phase of Fe-based superconductors, including FeSe, but its origin is not yet understood. Here we report a high resolution Angle-Resolved…

We analyze antiferromagnetism and superconductivity in novel $Fe-$based superconductors within the itinerant model of small electron and hole pockets near $(0,0)$ and $(\pi,\pi)$. We argue that the effective interactions in both channels…

We address two important issues that arise in recent studies of iron-based superconductivity. (1) Why are the T_c of A_xFe_{2-y}Se_2 and the single unit cell FeSe on SrTiO$_3$ so high despite both only have electron pockets? (2) What (if…

We apply a Hartree-Fock approximation to a two-orbital model proposed for Fe pnictide superconductors. It is found that the antiferromagnetic (AFM) order with the ordering vector Q=(pi,0) is realized. The AFM order appears simultaneously…

We analyze the dynamical response of a two-dimensional system of itinerant fermions coupled to a scalar boson $\phi$, which undergoes a continuous transition towards nematic order with $d-$wave form-factor. We consider two cases: (a) when…

The iron-based superconductors allow for a zoo of possible order parameters due to their orbital degrees of freedom. These order parameters are often written in an orbital basis, as this allows to distinguish their different symmetry.…

Neutron scattering, with its ability to measure the crystal structure, the magnetic order, and the structural and magnetic excitations, plays an active role in investigating various families of Fe-based high-Tc superconductors. Three…

We report the first photoemission study of Fe$_{1+x}$Te - the host compound of the newly discovered iron-chalcogenide superconductors (maximum T$_c$ $\sim$ 27K). Our results reveal a pair of nearly electron-hole compensated Fermi pockets,…

Using the continuum model for low energy non-interacting electronic structure of moir\'e van der Waals heterostructures developed by Bistritzer and MacDonald [1], we study the competition between spin, charge, and superconducting order in…

A major puzzle about the nature of the iron-based superconductivity appears in the case of the alkaline iron selenides. Compared to the iron pnictides, these systems have only electron Fermi pockets (i.e. no hole Fermi pockets) but…

The superconducting order parameter and LDOS spectra near an impenetrable surface are studied on the basis of selfconsistent calculations for a two band superconductor with nodeless extended s-+wave order parameter symmetry, as possibly…

We analyze superconductivity in a multi-orbital fermionic system near the onset of a nematic order, using doped FeSe as an example. We associate nematicity with a spontaneous polarization between $d_{\text{xz}}$ and $d_{\text{yz}}$ orbitals…

In strongly correlated electronic systems, several novel physical properties are induced by the orbital degree of freedom. In particular, orbital degeneracy near the Fermi level leads to spontaneous symmetry breaking, such as the nematic…

Electronic structure and the shape of the Fermi surface are known to be of fundamental importance for the superconducting instability in real materials. We demonstrate that such an instability may be explored by static Cooper pair…

We investigated the form of the orbital ordering in the electronic nematic phase of the Iron-based superconductors by applying a group theoretical analysis on a realistic five-band model. We find the orbital order can be either of the…

We study FeO, a Mott insulator in GGA and GGA+U approximations. In the GGA we find a multi-band metallic state with remarkable inter-band nesting between two $t_{2g}$ bands of Fermi surface, which signals possible instability towards an…

Electronic correlation is of fundamental importance to high temperature superconductivity. Iron-based superconductors are believed to possess moderate correlation strength, which combined with their multi-orbital nature makes them a…

Motivated by recent observation of nematicity in Moir\'{e} systems, we study three different orbital orders that potentially can happen in Moir\'{e} systems: (1) the nematic order; (2) the valley polarization; and (3) the "compass order".…

Strong correlations lead to emergent excitations at low energies. When combined with symmetry constraints, they may produce topological electronic states near the Fermi energy. Within this general framework, here we address the topological…