相关论文: NaFe$_{0.56}$Cu$_{0.44}$As: A pnictide insulating …

Spin-$1/2$ chains with alternating antiferromagnetic and ferromagnetic couplings have attracted considerable interest due to the topological character of their spin excitations. Here, using density functional theory and density matrix…

The phase diagram of non-hydrated Na(x)CoO(2) has been determined by changing the Na content x using a series of chemical reactions. As x increases from 0.3, the ground state goes from a paramagnetic metal to a charge-ordered insulator (at…

We use neutron scattering to study the structural and magnetic phase transitions in the iron pnictides CeFeAsO1-xFx as the system is tuned from a semimetal to a high-transition-temperature (high-Tc) superconductor through Fluorine (F)…

While the parent compounds of the cuprate high temperature superconductors (high-Tc's) are Mott insulators, the iron-pnictide high-Tc's are in the vicinity of a metallic spin density wave (SDW) state, which highlights the difference between…

The iron-based pnictide LaFe2As2 is not superconducting as-synthesized, but it becomes such below Tc around 12 K upon annealing, as a consequence of a structural transition from a phase with collapsed tetragonal crystal structure to an…

The presence of macroscopic phase separation between the superconducting and magnetic phases in \cfcaf is demonstrated by muon spin rotation (muSR) measurements conducted across their phase boundaries (x=0.05-0.15). The magnetic phase tends…

We investigate the pairing in iron pnictides in the coexistence phase, which displays both superconducting and antiferromagnetic orders. By solving the pairing problem on the Fermi surface reconstructed by long-range magnetic order, we find…

Using density functional theory calculations including an on-site Coulomb term, we explore electronic and possibly topologically nontrivial phases in $3d$ transition metal oxide honeycomb layers confined in the corundum structure…

The recent discovery of high-temperature superconductivity (HTSC) in doped Iron pnictides is the latest example of unanticipated behavior exhibited by $d$- and $f$-band materials. The symmetry of the SC gap, along with the mechanism of its…

Using angle-resolved photoemission spectroscopy, we studied the electronic structure of NaFe$_{1-x}$Co$_x$As from an optimally doped superconducting compound ($x=0.028$) to a heavily overdoped non-superconducting one ($x=0.109$). Similar to…

Semiconductor surfaces with narrow surface bands provide unique playgrounds to search for Mott-insulating state. Recently, a combined experimental and theoretical study [Phys. Rev. Lett. 114, 247602 (2015)] of the two-dimensional (2D) Sn…

Superconducting cuprates and pnictides composed of CuO2 or AsFe planes respectively with intercalated insulating layers, are at the crossroads of three families of crystalline solids: metals, doped Mott insulators, and ferroelectrics. In…

We present a brief review of the present day situation with studies of high-temperature superconductivity in iron pnictides and chalcogenides. Recent discovery of superconductivity with T_c > 30 K in A_xFe_{2-x/2}Se_2 (A=K,Cs,Tl,...)…

In copper-oxide and iron-based high temperature (high-$T_{\rm c}$) superconductors, many physical properties exhibit in-plane anisotropy, which is believed to be caused by a rotational symmetry-breaking nematic order, whose origin and its…

We examine electronic states of antiferromagnetic phase in iron pnictides by mean-field calculations of the optical conductivity. We find that a five-band model exhibiting a small magnetic moment, inconsistent with the first-principles…

The parent compounds of iron-based superconductors are magnetically-ordered bad metals, with superconductivity appearing near a putative magnetic quantum critical point. The presence of both Hubbard repulsion and Hund's coupling leads to…

We use neutron diffraction to study the temperature evolution of the average structure and local lattice distortions in insulating and superconducting potassium iron selenide K$_y$Fe$_{1.6+x}$Se$_2$. In the high temperature paramagnetic…

We report the results of a comprehensive spectroscopic ellipsometry study of NaCu2O2, a compound composed of chains of edge-sharing Cu2+O4 plaquettes and planes of Cu1+ ions in a O-Cu1+-O dumbbell configuration, in the spectral range…

We report evidence for multiband transport and an insulating low-temperature normal state in superconducting K$_{0.50}$Na$_{0.24}$Fe$_{1.52}$Se$_{2}$ with $T_{c}\approx 20$ K. The temperature-dependent upper critical field, $H_{c2}$, is…

FeSe has been extensively explored as a quantum material, primarily due to the observed highest superconducting transition temperature among Fe-based unconventional superconductors. Nonetheless, the electronic structure and the electron…