相关论文: Impurity-induced bound states inside the supercond…
The properties of iron-based superconductors (Fe-SCs) can be varied dramatically with the introduction of dopants and atomic defects. As a pressing example, FeSe, parent phase of the highest-$T_c$ Fe-SC, exhibits prevalent defects with…
We study the effect of a single non-magnetic impurity in A$_{y}$Fe$_{2-x}$Se$_{2}$ (A=K, Rb, or Cs) superconductors by considering various pairing states based on a three-orbital model consistent with the photoemission experiments. The…
We apply high resolution scanning tunneling microscopy to study intrinsic defect states of bulk FeSe. Four types of intrinsic defects including the type I dumbbell, type II dumbbell, top-layer Se vacancy and inner-layer Se-site defect are…
Based on a two-orbit four-band tight binding model, we investigate the low-lying electronic states around the interstitial excess Fe ions in the iron-based superconductors by using T-matrix approach. It is shown that the local density of…
Several Fe chalcogenide superconductors without hole pockets at the Fermi level display high temperature superconductivity, in apparent contradiction to naive spin fluctuation pairing arguments. Recently, scanning tunneling microscopy…
We study impurity bound states and impurity-induced order in the superconducting state of LiFeAs within a realistic five-band model based on the band structure and impurity potentials obtained from density functional theory (DFT). In…
Measurements of the local density of states near impurities can be useful for identifying the superconducting gap structure in alkali doped iron chalcogenide superconductors K_xFe_{2-y}Se_2. Here, we study the effects of nonmagnetic and…
In this work, we investigate the local density of states (LDOS) near a magnetic impurity in single-layer FeSe superconductors. The two-orbital model with spin-orbit coupling proposed in Ref. [{\emph{Phys. Rev. Lett.} \textbf{119}, 267001…
A pronounced local in-gap zero-energy bound state (ZBS) has been observed by recent scanning tunneling microscopy (STM) experiments on the interstitial Fe impurity (IFI) and its nearest-neighboring (nn) sites in…
Recently topological superconducting states has attracted a lot of interest. In this work, we consider a topo- logical superconductor with $Z_2$ topological mirror order [1] and s$\pm$-wave superconducting pairing symmetry, within a…
We discuss the universal theory of localized impurities in the paramagnetic state of 2D antiferromagnets where the spin gap is assumed to be significantly smaller than a typical exchange energy. We study the impurity spin susceptibility…
The low energy band structure of the FeAs based superconductors is fitted by a tight binding model with two Fe ions per unit cell and two degenerate orbitals per Fe ion. Based on this, superconductivity with extended s-wave pairing symmetry…
We study the presence of impurity bound states within a five-band Hubbard model relevant to iron-based superconductors. In agreement with earlier studies, we find that in the absence of Coulomb correlations there exists a range of repulsive…
Most superconducting materials exhibit a vanishing density of states at the Fermi level and Anderson's theorem posits that the superconducting gap is robust against nonmagnetic disorder. Although dilute magnetic impurities lead to localized…
We use scanning tunneling microscopy (STM) to study magnetic Fe impurities intentionally doped into the high-temperature superconductor Bi$_{2}$Sr$_{2}$Ca$_{2}$CuO$_{8+\delta}$. Our spectroscopic measurements reveal that Fe impurities…
We have studied the effect of a single nonmagnetic impurity in the recently discovered (K,Tl)Fe$_x$Se$_2$ superconductors, within both a toy two-band model and a more realistic five-band model. We have found that, out of five types of…
We demonstrate that the differential conductance, $dI/dV$, measured via spectroscopic imaging scanning tunneling microscopy in the doped iron chalcogenide FeSe$_{0.45}$Te$_{0.55}$, possesses a series of characteristic features that allow…
We analyze the density of state (DOS) and a non-magnetic impurity effect in electron-doped cuprates starting from two different scenarios: the $d_{x^{2}-y^{2}}$-wave superconductivity coexisting with antiferromagnetic spin density wave…
With the aim at understanding the non-monotonic $d_{x^{2}-y^{2}}$-wave gap, we analyze the local electronic structure near impurities in the electron-doped cuprate superconductors. We find that the local density of states near a…
We review the progress of nonmagnetic impurity doping study on the Fe-based superconductors. On the theoretical side, two highly potential candidates for the pairing symmetry order parameter, i.e. the multi-gap s++ and s+- wave models, have…