Local density of states around two nonmagnetic impurities in cuprate superconductors

Abstract

The local density of states (LDOS) around two nonmagnetic impurities which are located at different sites is studied within the two-dimensional t-J-U model. The order parameters are determined in a self-consistent way with the Gutzwiller projected mean-field approximation and the Bogoliubov-de Gennes theory. When the two impurities are located one or two sites away, we find the superconductivity coherence peaks are more strongly suppressed and the zero-energy peak (ZEP) has split into two peaks. Whereas when the two impurities are located next to each other, the ZEP vanished, and LDOS does not change a lot compared with the case away from the impurities.

Quasiparticle scattering interference in the renormalized Hubbard model

“…These peaks at well-defined wavevectors q i obeys the octet model [6]. Theoretically, within the phenomenological d-wave Bardeen-CooperSchrieffer (BCS) formalism [7][8][9][10][11][12][13], the properties of the quasiparticle and its related quasiparticle scattering interference phenomenon have been studied by considering the effect of impurity, and these works show that a single or few impurities in a d-wave superconducting state play a crucial role in explaining the results observed by STM experiments [5,6]. Moreover, within the framework of the kinetic energy driven SC mechanism [14][15][16], the key features of the quasiparticle scattering interference phenomenon in cuprate superconductors in the SC state are captured by considering the single impurity.…”