Abstract With cuprate superconductors in mind, we study the effects of point-type impurity potential (V) on a d x 2−y 2 -wave superconducting (d-SC) state in a strongly correlated squarelattice Hubbard model (U/t = 12) with a diagonal transfer (t′), using a variational Monte Carlo method. At half filling, insulator-to-conductor (filling-control-type Mott) transitions occur at <?CDATA $V={V}_{U}^{(\pm )}\sim \pm U$ ?> V = V U ( ± ) ∼ ± U . The phase realized for <?CDATA $V\lt {V}_{U}^{(-)}$ ?> V < V U ( − ) is robust d-SC and the charge carriers are holes, whereas for <?CDATA $V\gt {V}_{U}^{(+)}$ ?> V > V U ( + ) a metallic (or weak d-SC) state appears with charge carriers of electrons. For a partially-filled case where the impurity density is equal to the doping rate, a d-SC-to-insulator transition arises at V ≡ V M ∼ 4t. In the weak-|V| phases, the impurity effects in the electron distribution are smeared out by the screening effect, whereas in the strong-|V| phases, the electron distribution directly depend on the impurity configurations.Abstract With cuprate superconductors in mind, we study the effects of point-type impurity potential (V) on a d x 2−y 2 -wave superconducting (d-SC) state in a strongly correlated squarelattice Hubbard model (U/t = 12) with a diagonal transfer (t′), using a variational Monte Carlo method. At half filling, insulator-to-conductor (filling-control-type Mott) transitions occur at <?CDATA $V={V}_{U}^{(\pm )}\sim \pm U$?> V = V U ( ± ) ∼ ± U . The phase realized for <?CDATA $V\lt {V}_{U}^{(-)}$?> V < V U ( − ) is robust d-SC and the charge carriers are holes, whereas for <?CDATA $V\gt {V}_{U}^{(+)}$?> V > V U ( + ) a metallic (or weak d-SC) state appears with charge carriers of electrons. For a partially-filled case where the impurity density is equal to the doping rate, a d-SC-to-insulator transition arises at V ≡ V M ∼ 4t. In the weak-|V| phases, the impurity effects in the electron distribution are smeared out by the screening effect, whereas in the strong-|V| phases, the electron distribution directly depend on the impurity configurations.

Journal of Physics Conference SeriesSep 1, 20190 citations

Interacting molecules on the surface of a dx2−y2 -wave superconductor

Roy H. Nyberg, Dirk K. Morr

We study interacting molecules on the surface of a ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$-wave superconductor. We show that the interplay between the molecules' excitation spectrum and quantum interference of the scattered host electrons leads to a series of characteristic signatures and intriguing quantum effects in the superconductor's local density of states. We demonstrate that these effects give insight into both the nature of the superconducting pairing correlations and the intermolecular interactions.We study interacting molecules on the surface of a ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$-wave superconductor. We show that the interplay between the molecules' excitation spectrum and quantum interference of the scattered host electrons leads to a series of characteristic signatures and intriguing quantum effects in the superconductor's local density of states. We demonstrate that these effects give insight into both the nature of the superconducting pairing correlations and the intermolecular interactions.

Physical Review BJun 10, 20053 citations

V={V}_{U}^{(\pm )}\sim \pm U

?> V = V U ( ± ) ∼ ± U . The phase realized for <?CDATA

V\lt {V}_{U}^{(-)}

?> V < V U ( − ) is robust d-SC and the charge carriers are holes, whereas for <?CDATA

V\gt {V}_{U}^{(+)}

?> V > V U ( + ) a metallic (or weak d-SC) state appears with charge carriers of electrons. For a partially-filled case where the impurity density is equal to the doping rate, a d-SC-to-insulator transition arises at V ≡ V M ∼ 4t. In the weak-|V| phases, the impurity effects in the electron distribution are smeared out by the screening effect, whereas in the strong-|V| phases, the electron distribution directly depend on the impurity configurations.