相关论文: 'Pi State' Induced by Impurities with a Repulsive …
We study the effect of density-assisted hopping on different dimerized lattice geometries, such as bilayers and ladder structures. We show analytically that the density-assisted hopping induces an attractive interaction in the lower…
The unique property of Coulomb interaction in strict one-dimensional (1D) system is revealed that the Coulomb repulsion energy of paired electrons is divergent. As consequences, electrons in 1D system can not doubly occupy the same spatial…
Effects of impurities and disorder on quasiparticle spectrum in superconducting iron pnictides are considered. Possibility for occurrence of localized energy levels due to impurities within the superconducting gap and the related…
System-environment interaction may introduce dynamic destruction of quantum coherence, resulting in a special representation named as pointer states. Here, pointer states of an open electronic system are studied. The decoherence effect is…
We study proximity coupling between a superconductor and counter-propagating gapless modes arising on the edges of Abelian fractional quantum Hall liquids with filling fraction $\nu=1/m$ (with $m$ an odd integer). This setup can be utilized…
We discuss a reduction of superconducting transition temperature by the intersite Coulomb repulsion for the d-wave pairing in cuprates. We compare the results found for the spin-fermion model and the extended Hubbard model. We argue that in…
It has been observed that the effect of magnetic impurities in a superconductor is drastically different depending on whether the host superconductor is in a crystalline or an amorphous state. Based on the recent theory of Kim and…
We investigate the mutual influence of impurities in two-dimensional d-wave superconductors involving self-consistent solutions of the Bogoliubov-de Gennes equations. The local order parameter suppression, the local density of states (LDOS)…
We examine the role of order-parameter suppression in the development of low-energy peaks (i.e., resonances) in the tunneling density of states near a non-magnetic impurity in a d-wave superconductor. Without order-parameter suppression,…
We propose a new qubit consisting of a superconducting ring with two ordinary zero junctions and one ferromagnetic pi junction. In the system, two degenerate stable states appear in the phase space without an external magnetic field because…
Renormalization of the Coulomb interaction in layered metals results in a strongly anisotropic plasma mode with low frequencies for small components of wave vector in the in-plane direction. Interaction of electrons with this mode was found…
The current study is motivated by a difficulty to reconcile between particle number conservation and superconductivity. An alternative modeling, which is based on the hypothesis that disentanglement spontaneously ocuurs in quantum systems,…
We study the effect of Coulomb repulsion between oxygen holes on the London penetration depth $\lambda$ based on the concept of spin-polaron nature of Fermi quasiparticles in cuprates superconductors. It is shown that for the generally…
Coulomb repulsion can, counterintuitively, mediate Cooper pairing via the Kohn-Luttinger mechanism. However, it is commonly believed that observability of the effect requires special circumstances -- e.g., vicinity of the Fermi level to van…
We study by Variational Monte Carlo an extended Hubbard model away from half filled band density which contains two competing nearest-neighbor interactions: a superexchange $J$ favoring d-wave superconductivity and a repulsion $V$ opposing…
Unconventional symmetries of the order parameter allowed some researchers to maintain that a purely repulsive interaction between electrons provides superconductivity without phonons in a number of high-temperature superconductors. It is…
The local density of states (LDOS) and its Fourier component induced by a unitary impurity in a supercurrent-carrying d-wave superconductor are investigated. Both of these quantities possess a reflection symmetry about the line passing…
We introduce a toy model that allows us to study the physical properties of a spin impurity coupled to the electrons in the superconducting island. We show that when the coupling of the spin is of the order of the superconducting gap two…
A strong nonmagnetic impurity can induce a resonance state in the d-wave superconducting state. As far as magnetic properties are concerned, this resonance state behaves effectively like a free moment. It leads to a Curie-Weiss-like…
Josephson current for a system consisting of an Anderson impurity weakly coupled to two unconventional superconductors is studied and shown to be driven by a surface zero energy (mid-gap) bound-state. The repulsive Coulomb interaction in…