Related papers: Ab Initio Calculation of Impurity Effects in Coppe…
In conventional s-wave superconductors, only magnetic impurities exhibit impurity bound states, whereas for an s+- order parameter they can occur for both magnetic and non-magnetic impurities. Impurity bound states in superconductors can…
Motivated by recent scanning tunneling microscopy experiments on surfaces of Bi$_{1-x}$Sb$_{x'}$\cite{yazdanistm,gomesstm} and Bi$_2$Te$_3$,\cite{kaptunikstm,xuestm} we theoretically study the electronic structure of a 3-dimensional (3D)…
Based on a Fermi liquid picture, the temperature effect on the impurity-induced spatial modulation of local density of states (LDOS) is investigated for the d-wave superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, in the context of scanning…
Experimental results obtained by using x-ray absorption spectroscopy show that the configurations of Cu sites in the CuO2 plane of Bi 2:2:1:2 high Tc superconductors are not homogeneous. Different Cu sites are characterized by short 0.23 nm…
We review recent developments in our understanding of how impurities influence the electronic states in the bulk of superconductors. Our focus is on the quasi-localized states in the vicinity of impurity sites in conventional and…
We investigate the electronic structure of cobalt atoms on a copper surface and in a copper host by combining density functional calculations with a numerically exact continuous-time quantum Monte Carlo treatment of the five-orbital…
In a recent Letter, Luo et al. (Phys. Rev. Lett. 92, 256602 (2004)) analyze the Fano line shapes obtained from scanning tunneling spectroscopy (STS) of transition metal impurities on a simple metal surface, in particular of the Ti/Au(111)…
Several material families show competition between superconductivity and other orders. When such competition is driven by doping, it invariably involves spatial inhomogeneities which can seed competing orders. We study impurity-induced…
The effect of non-magnetic Zn impurity on superconductivity in electron-type pnictide superconductor LaFe$_{0.925-y}$Co$_{0.075}$Zn$_y$AsO is studied systematically. The optimally doped LaFe$_{0.925}$Co$_{0.075}$AsO without Zn impurity…
Non-magnetic impurities in iron-based superconductors can provide an important tool to understand the pair symmetry and they can influence significantly the transport and the superconducting behaviour. Here, we present a study of the role…
We apply a recently developed method combining first principles based Wannier functions with solutions to the Bogoliubov-de Gennes equations to the problem of interpreting STM data in cuprate superconductors. We show that the observed…
We obtain general expressions for the residual density of states, electrical conductivity and thermal conductivity for non-unitary superconductors due to impurity scattering. We apply the results to the so-called `B phase' of PrOs4Sb12,…
We revisit the theory of the Kondo effect observed by a scanning-tunneling microscope (STM) for transition-metal atoms (TMAs) on noble-metal surfaces, including $d$ and $s$ orbitals of the TMA, surface and bulk conduction states of the…
The quantum interference between two nonmagnetic impurities is studied numerically in both the d-wave superconducting (DSC) and the d-density wave (DDW) state. In all calculations we include the tunnelling through excited states from the…
Band structure calculations are presented for large supercells of Ba$_2$CuO$_4$ (BCO) with O-vacancies in planar or apic al positions, and of superoxygenated La$_2$CuO$_4$ (LCO) with oxygen interstitials in the La$_2$O$_2$ layers. It is…
The electron-electron scattering rate of low-energy quasiparticles is computed perturbatively for a two-dimensional metal with a partially nested Fermi surface, a weak electron-electron interaction and an energy-independent impurity…
Herein, we invesgate the consequence of local voltage pulses on the adsorption state of single indigo molecules on the Cu(111) surface as well as on the atomic structure underneath the molecule. With a scanning tunneling microscope, at 5 K,…
By comparing experimental results obtained in the study of the electron transport and magnetic properties of samples of lightly strontium-substituted lanthanum cuprates and the results of a previously published numerical analysis in the…
The recently observed properties of quasiparticle resonant states near impurities on the surface of superconducting BSCCO demonstrate that in-plane Andreev processes are either absent or phase-incoherent. Analysis of the spectral and…
We present results for the spectral properties of Kondo impurities in nanoscopic systems. Using Wilson's renormalization group we analyze the frequency and temperature dependence of the impurity spectral density for impurities in small…