Related papers: Large-N limit of a magnetic impurity in unconventi…
We present theoretical investigation of a single magnetic impurity in a d-wave superconductor using the large N limit. It is shown that the Kondo screening occurs only in the presence of the particle-hole asymmetry. We find analytical…
We have investigated the effect of nonmagnetic impurities on the quasi-one-dimensional unconventional density wave (UDW) ground state. The thermodynamics were found to be close to those of a d-wave superconductor in the Born limit. Four…
We investigate the effect of strong, nonmagnetic impurities on quasi-one-dimensional conventional and unconventional density waves (DW and UDW). The conventional case remains unaffected similarly to s-wave superconductors in the presence of…
Unconventional density waves (UDW) are one of the ground states in metallic crystalline solids and have been speculated already in 1968. However, more focused studies on UDW started only recently, perhaps after the identification of the low…
Unconventional density wave (UDW) has been speculated as a possible electronic ground state in excitonic insulator in 1968. Recent surge of interest in UDW is partly due to the proposal that the pseudogap phase in high T_c cuprate…
The Kondo effects of an Anderson impurity embedded into a d-wave superconductor is studied. Within the slave-boson mean-field approach, the derived Bogoliubov-de Gennes equations are solved via exact diagonalization. We show that a critical…
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…
We derive a solvable resonant-level type model, to describe an impurity spin coupled to zero-energy bound states localized at the edge of a one dimensional d-wave superconductor. This results in a two-channel Kondo effect with a quite…
Recently many people discuss unconventional density waves (i.e. unconventional charge density waves (UCDW) and unconventional spin density waves (USDW)). Unlike in conventional density waves, the quasiparticle spectrum in these systems is…
We investigate the Kondo effect in two-dimensional disordered electron systems using a finite-temperature quantum Monte Carlo method. Depending on the position of a magnetic impurity, the local moment is screened or unscreened by the spin…
We discuss the dynamics of magnetic moments in d-wave superconductors, in particular we focus on moments induced by doping non-magnetic impurities into cuprates. The interaction of such moments with the Bogoliubov quasiparticles of the…
Recently Chakravarty {\em et al.} proposed an ordered $d$-density wave (DDW) state as an explanation of the pseudogap phase in underdoped high-temperature cuprates. We study the competition between the DDW and superconducting ordering based…
It has been proposed, that unconventional density waves (UDW) are possible candidates for systems with hidden order parameter. Unlike in conventional density waves, no periodic modulation of either the charge-, or the spin-density is…
We propose a novel spin density wave (SDW) state as a possible mechanism of the anomalous antiferromagnetism, so-called the micromagnetism, in URu_2Si_2 below 17.5[K]. In this new SDW, the electron-hole pair amplitude changes its sign in…
We investigate the boundary phenomena that arise in a finite-size $XX$ spin chain interacting through an $XX$ interaction with a spin$-\frac{1}{2}$ impurity located at its edge. Upon Jordan-Wigner transformation, the model is described by a…
We study the Kondo effect due to the nonmagnetic impurity, e.g., Zn, in high-T_c cuprates based on the spin-change separated state. In the optimal or overdoped case with the Kondo screening, the residual resistivity is dominated by the…
We have investigated the collective modes of unconventional charge and spin density waves (UCDW, USDW) in quasi-one dimensional systems in random phase approximation. The density correlator regains its normal state form due to the phase…
The Kondo effect arises from many-body interactions between localized magnetic impurities and conduction electrons, affecting electronic properties at low temperatures. In this study, we investigate the Kondo effect within a two-dimensional…
The quasiparticle states around a nonmagnetic impurity in electron-doped iron-based superconductors with spin-density-wave (SDW) order are investigated as a function of doping and impurity scattering strength. In the undoped sample, where a…
Quantum spin impurities coupled to superconductors are under intense investigation for their relevance to fundamental research as well as the prospects to engineer novel quantum phases of matter. Here we develop a large-$N$ mean-field…