Related papers: Gossamer bulk high-temperature superconductivity i…
High-temperature superconductivity in cuprates emerges upon doping the parent Mott insulator. Robust signatures of the low-doped electronic state include a Hall carrier density that initially tracks the number of doped holes and the…
The importance of electron-hole interband interactions is widely acknowledged for iron-pnictide superconductors with high transition temperatures (Tc). However, high-Tc superconductivity without hole carriers has been suggested in FeSe…
The characteristics of Fe-based superconductors are manifested in their electronic, magnetic properties, and pairing symmetry of the Cooper pair, but the latter remain to be explored. Usually in these materials, superconductivity coexists…
FeSe is a fascinating superconducting material at the frontier of research in condensed matter physics. Here we provide an overview on the current understanding of the electronic structure of FeSe, focusing in particular on its low energy…
We report the novel preparation of single crystals of tetragonal iron sulfide, FeS, which exhibits a nearly ideal tetrahedral geometry with S--Fe--S bond angles of 110.2(2) $^\circ$ and 108.1(2) $^\circ$. Grown via hydrothermal…
Recent experimental and theoretical developments in high-temperature superconductivity are reviewed, and the empirically asymmetric behavior between hole-doped and electron-doped cuprates is contrasted. A number of phenomena previously…
The importance of antiferromagnetic fluctuations are widely acknowledged in most unconventional superconductors. In addition, cuprates and iron pnictides often exhibit unidirectional (nematic) electronic correlations, including stripe and…
Superconducting FeSe single crystals of (001) orientation are synthesized via a hydrothermal ion-release route. An Ising spin-nematic order is identified by our systematic measurements of in-plane angular-dependent magnetoresistance (AMR)…
Our recent year's studies of the prototypal FeSe and molecule-intercalated (Li,Fe)OHFeSe superconductor systems are briefly reviewed here, with emphasis on experimental observations of the link between the superconductivity and normal-state…
CsCa$_2$Fe$_4$As$_4$F$_2$ is a newly discovered iron-based superconductor with $T_\mathrm{c}\sim$ 30 K containing double Fe$_2$As$_2$ layers that are separated by insulating Ca$_2$F$_2$ spacer layers. Here we report the transport and…
The role of electronic Coulomb correlations in iron-based superconductors is an important open question. We provide theoretical evidence for strong correlation effects in the FeSe compound, based on dynamical mean field calculations. A…
The pressure dependence, up to 11.3 kbar, of basic parameters of the superconducting state, such as the critical temperature (Tc), the lower and the upper critical fields, the coherence length, the penetration depth, and their anisotropy,…
By interpreting various experimental data for the new high temperature FeAs type superconductors in terms of lattice mediated multi gap superconductivity, it is shown that these systems strongly resemble MgB2, however, with the distinction…
Dependences of low temperature behavior and anisotropy of various physical quantities for pure unconventional superconductors upon a particular form of momentum direction dependence for the superconducting order parameter (within the…
It is known that iron selenide superconductors exhibit unique characteristics distinct from iron pnicitides, especially in the electron-doped region. However, acomprehensive study of continuous carrier doping ang the corresponding crystal…
(Li0.8Fe0.2)OHFeSe is a newly-discovered intercalated iron-selenide superconductor with a Tc above 40 K, which is much higher than the Tc of bulk FeSe (8 K). Here we report a systematic study of (Li0.8Fe0.2)OHFeSe by low temperature…
High-temperature superconductivity occurs near antiferromagnetic instabilities and nematic state. Debate remains on the origin of nematic order in FeSe and its relation with superconductivity. Here, we use transport, neutron scatter- ing…
Iron based narrow gap semiconductors such as FeSi, FeSb2, or FeGa3 have received a lot of attention because they exhibit a large thermopower, as well as striking similarities to heavy fermion Kondo insulators. Many proposals have been…
The superconductor FeSe is of intense interest thanks to its unusual non-magnetic nematic state and potential for high temperature superconductivity. But its Cooper pairing mechanism has not been determined. Here we use Bogoliubov…
The sulfur-substituted FeSe, FeSe$_{1-x}$S$_{x} $, is one of the unique systems that provides an independent tunability of nematicity, antiferromagnetism and superconductivity under pressure ($p$). Recently Rana et al. [Phys. Rev. B 101,…