Related papers: FeSe and the missing electron pocket problem
FeSe$_{1-x}$S$_x$ remains one of the most enigmatic systems of Fe-based superconductors. While much is known about the orthorhombic parent compound, FeSe, the tetragonal samples, FeSe$_{1-x}$S$_x$ with x>0.17, remain relatively unexplored.…
To understand the rich electronic phase diagram in FeSe under pressure that vividly demonstrates the strong interplay between the nematicity, magnetism and superconductivity, we analyze the electronic states by including the higher-order…
The magnetotransport behaviour inside the nematic phase of bulk FeSe reveals unusual multiband effects that cannot be reconciled with a simple two-band approximation proposed by surface-sensitive spectroscopic probes. In order to understand…
Central issues in the electronic structure of underdoped cuprate superconductors are to clarify the shape of the Fermi surfaces and the origin of the pseudogap. On the basis of the model proposed by Kamimura and Suwa, which bears important…
Iron-based superconductors are well known for their complex interplay between structure, magnetism and superconductivity. FeSe offers a particularly fascinating example. This material has been intensely discussed because of its extended…
The interplay of orbital and spin degrees of freedom is the fundamental characteristic in numerous condensed matter phenomena, including high temperature superconductivity, quantum spin liquids, and topological semimetals. In iron-based…
Mechanism of unconventional superconductivity in FeSe has been intensely scrutinized recently because of a variety of exotic properties unprecedented for other iron-based superconductors. A central unanswered question concerns the origin of…
The mechanism of high temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics. The electronic structure, in particular the Fermi surface topology, is considered to play an…
The electronic energy structures and magnetic properties of layered superconductors $R$Ni$_2$B$_2$C, $R$Fe$_4$Al$_8$ and FeSe are systematically studied, by using the density functional theory (DFT). The calculations allowed us to reveal a…
We reiterate, in more details, our previous proposal of using quasi-particle interference to determine the pairing form factor in iron-based superconductors. We also present our functional renormalization group(FRG) results on LaFePO and…
The lack of nesting of the electron and hole Fermi-surface sheets in the Fe-based superconductor LiFeAs, with a critical temperature of 18 K, has led to questions as to whether the origin of superconductivity in this material might be…
Although nodeless superconducting gap has been observed on the large Fermi pockets around the zone corner in KxFe2-ySe2, whether its pairing symmetry is s-wave or nodeless d-wave is still under intense debate. Here we report an isotropic…
The influence of tensile strain in the ab-plane on crystal and electronic structure of FeTe has been studied ab initio. In superconducting FeSe the Fermi surface nesting with a vector q~(0.5,0.5)(2\pi /a) is believed to be crucial for…
Nematicity is ubiquitous in electronic phases of high transition temperature superconductors, particularly in iron-based superconductors (IBSCs). Order parameter that characterizes the nematic phase has been investigated in momentum space,…
An SDW antiferromagnetic (SDW-AF) low temperature phase transition is generally observe and the AF spin fluctuations are considered to play an important role for the superconductivity paring mechanism in FeAs superconductors. However, a…
Recent quantum oscillation experiments in underdoped high temperature superconductors seem to imply two paradoxes. The first paradox concerns the apparent non-existence of the signature of the electron pockets in angle resolved…
Finding of unconventional superconductivity (USC) in FeSe in an electronic "normal" state with broken $C_{4v}$ rotational symmetry testifies to the diversity of pairing states in Fe-based superconductors. Moreover, such USC emerges as a…
The relationship between antiferromagnetic (AFM) spin fluctuations (SF), nematic fluctuations, and superconductivity (SC) has been central to understanding the pairing mechanism in iron-based superconductors (IBSCs). Iron chalcogenides,…
The role of nematic order for the mechanism of high-temperature superconductivity is highly debated. In most iron-based superconductors (IBS) the tetragonal symmetry is broken already in the normal state, resulting in orthorhombic lattice…
A very fundamental and unconventional characteristic of superconductivity in iron-based materials is that it occurs in the vicinity of {\it two} other instabilities. Apart from a tendency towards magnetic order, these Fe-based systems have…