相关论文: Electron correlation and impurity-induced quasipar…
Two scenarios, i.e., the anisotropic s-wave pairing (the s-wave scenario) and the d-wave pairing coexisting with antiferromagnetism (the coexisting scenario) have been introduced to understand some of seemingly s-wave like behaviors in…
The Hubbard on-site repulsion $U$ between opposite spin electrons on the same atomic orbital is widely regarded to be the most important source of electronic correlation in solids. Here we extend the Hubbard model to account for the fact…
The effect of the Coulomb repulsion of holes on the Cooper instability in an ensemble of spin-polaron quasiparticles has been analyzed, taking into account the peculiarities of the crystallographic structure of the CuO$_2$ plane, which are…
We study sharp low-energy resonance peaks in the local density of states (LDOS) induced by Zn impurities or possible Cu vacancies in superconducting Bi_2Sr_2CaCu_2O_{8+delta}. The measured structure of these near-zero-bias resonances is…
In materials with strong local Coulomb interactions, simple defects such as atomic substitutions strongly affect both macroscopic and local properties of the system. A nonmagnetic impurity, for instance, is seen to induce magnetism nearby.…
We study the properties of a quantum impurity embedded in a superconducting host. The superconductor is described by the negative U Hubbard model while the impurity introduces a repulsive interaction to the system. We discuss the influence…
The quantum interference effect on the quasiparticle density of states (DOS) is studied with the diagrammatic technique in two-dimensional d-wave superconductors with dilute nonmagnetic impurities both near the Born and near the unitary…
Quasiparticle interference has been used frequently for the purpose of unraveling the electronic states in the vicinity of the Fermi level as well as the nature of superconducting gap in the unconventional superconductors. Using the…
We investigate the issues of competing orders and quantum criticality in cuprate superconductors via experimental studies of the high-field thermodynamic phase diagrams and the quasiparticle tunneling spectroscopy. Our results suggest…
We study the quasiparticle resonance states near strong impurities in the mixed state of a d-wave superconductor. These states give rise to zero-bias peaks in the local density of states, observed in scanning tunneling microscopy…
Correlations between electrons and the effective dimensionality are crucial factors that shape the properties of an interacting electron system. For example, the onsite Coulomb repulsion, U, may inhibit, or completely block the intersite…
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…
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…
We investigate the impurity resonant state induced by non-magnetic impurities in d-wave cuprate superconductors in two different impurity models: (i) in a pure potential scattering model within the T-matrix approach and (ii) in a Bose-Fermi…
We have studied tunneling-mediated local density of states (LDOS) of the surface layer of a bilayer cuprate, where a Zn impurity is located on the second Cu-O layer. When the tunneling strength between two Cu-O layers is larger than a…
The absence of localization of impurity-induced low-energy quasiparticle states in a two-dimensional $d$-wave superconductor is argued for any amount of disorder in the limit of unitary scatterers. This surprising result follows from the…
The quasiparticle scattering interference (QSI) is intimately related to the nature of the quasiparticle and of its interplay with a variety of electronic orders and superconductivity. Here starting from the microscopic octet scattering…
We address the problem of resistivity saturation observed in materials such as the A-15 compounds. To do so, we calculate the resistivity for the Hubbard-Holstein model in infinite spatial dimensions to second order in on-site repulsion…
We study the competition between an instantaneous local Coulomb repulsion and a boson mediated retarded attraction, as described by the Hubbard-Holstein model. Restricting to the case of half filling, the ground-state phase diagram and the…
We model a quantum dot-array (with one electron per dot) comprising of two (or more than two) coupled dots by an extended Hubbard Hamiltonian to investigate the role played by the inter-dot tunneling amplitude td, together with intra-dot…