Related papers: Intra-inter band pairing, order parameter symmetry…
The well-known Pavarini et al. [Phys. Rev. Lett. 87, 047003 (2001)] correlation between the critical temperature $T_{c,\,\mathrm{max}}$ and the shape of the Fermi contour of the optimally hole-doped cuprates is explained within the…
The recent discovery of high-temperature superconductivity in single-layer iron selenide has generated significant experimental interest for optimizing the superconducting properties of iron-based superconductors through the lattice…
In flat-band superconductors, the electron pairing is strongly enhanced so that the critical temperature scales linearly with the interaction strength. Identifying the governing pairing mechanism in flat-band superconducting systems is…
The rich variety of iron-based superconductors and their complex electronic structure lead to a wide range of possibilities for gap symmetry and pairing components. Here we solve in the 2-Fe Brillouin zone the full frequency-dependent…
We report the results of our in-depth analysis of spectroscopic and thermodynamic properties of a multi-orbital metal, like FeSe, which first develops a nematic order and then undergoes a transition into a superconducting state, which…
We consider the id-density wave (DDW) order, representing the pseudo-gap (PG) state, and the d-wave superconductivity (DSC)within the BCS framework for the two-dimensional (2D) fermion system on a square lattice starting with a mean-field…
We study the existence of intraband and interband pairing in the extended two band and three-band Hubbard model. It is shown that including interband pairing significantly increases the superconducting critical temperature in comparison…
The BCS-BEC crossover from strongly overlapping Cooper pairs to non-overlapping composite bosons in the strong coupling limit has been a long-standing issue of interacting many-body fermion systems. Recently, FeSe semimetal with hole and…
We consider a planar heterostructure consisting of a normal metal in proximity to an antiferromagnetic insulator, with an interlayer exchange coupling between the metal and the insulator. The coupling to the two sublattices of the…
Bulk FeSe is a special iron-based material in which superconductivity emerges inside a well-developed nematic phase. We present a microscopic model for this nematic superconducting state, which takes into account the mixing between $s-$wave…
In iron-based superconductors, the two Fe atoms in the unit cell are typically related by crystal symmetries; therefore, we expect no intra-unit cell variations in the superconducting gap. However, recent experiments have challenged this…
In order to investigate details of the superconducting (SC) gap in the iron-chalcogenide superconductors, the specific heat, C, of FeSe_1-x_Te_x_ with x=0.6-1 has been measured in magnetic fields. Using the two-gap model, it has been found…
The interplay between the band Jahn-Teller distortion and the superconductivity is studied for the system whose Fermi level lies in two-fold degenerate band. Assuming that the lattice distortion is coupled to the orbital electron density…
We carried out a comprehensive study of the electronic, magnetic, and thermodynamic properties of Ni-doped ZrTe$_2$. High quality Ni$_{0.04}$ZrTe$_{1.89}$ single crystals show a possible coexistence of charge density waves (CDW,…
We study the competition between various forms of density-wave-like order parameters that may arise in multi-orbital correlated materials with strong spin-orbit coupling (SOC) within a renormalization-group (RG) approach. The calculations…
Superconductors at temperatures below the critical temperature $T_c$ can be modeled as a mixture of Fermi and Bose gases, where the Fermi gas consists of conduction electrons and the Bose gas comprises Cooper pairs. This simple model…
We study the spectral and thermodynamic properties of inhomogeneous d-wave superconductors within a model where the inhomogeneity originates from atomic scale pair disorder. This assumption has been shown to be consistent with the small…
For a newly discovered iron-based high $T_c$ superconductor LaFeAsO$_{1-x}$F$_x$, we have constructed a minimal model, where inclusion of all the five Fe $d$ bands is found to be necessary. Random-phase approximation is applied to the model…
We consider competition of Kondo effect and s-wave superconductivity in heavy fermion and mixed valence superconductors, using the phenomenological approach for the periodic Anderson model. Similar to the well known results for…
Despite the intense theoretical and experimental effort, an understanding of the superconducting pairing mechanism of the high-temperature superconductors, leading to an unprecedented high transition temperature $T_c$, is still lacking.…