Impurity Scattering Effects in STM Studies of High-T_c Superconductors

TL;DR

This paper investigates how impurity scattering affects local density of states in high-T_c superconductors using a Bogoliubov-de Gennes approach combined with Gutzwiller mean-field theory, revealing suppressed potential scattering and enhanced hopping/exchange variations.

Contribution

It introduces a combined BdG and Gutzwiller mean-field framework to study impurity effects in strongly correlated high-T_c cuprates, highlighting the differential impact of potential versus hopping/exchange impurities.

Findings

Potential impurity scattering is greatly suppressed.

Local variation of hoppings/exchanges is enhanced.

Provides insights into impurity effects in disordered high-T_c systems.

Abstract

Recent STM measurements have observed many inhomogeneous patterns of the local density of states on the surface of high-T_c cuprates. As a first step to study such disordered strong correlated systems, we use the BdG equation for the t-t'-t"-J model with an impurity. The impurity is taken into account by a local potential or local variation of the hopping/exchange terms. Strong correlation is treated by a Gutzwiller mean-field theory with local Gutzwiller factors and local chemical potentials. It turned out that the potential impurity scattering is greatly suppressed, while the local variation of hoppings/exchanges is enhanced.