Quasiparticle scattering and local density of states in the d-density wave phase

TL;DR

This paper investigates how single-impurity scattering affects the local density of states in high-temperature cuprates, comparing different ordered states to identify signatures of the d-density wave phase.

Contribution

It provides a comparative analysis of quasiparticle interference patterns in DSC, DDW, and coexisting states, highlighting distinctive features of the DDW order.

Findings

Interference patterns differ significantly above the DSC gap in coexisting states.

DDW state exhibits stronger coherence factor effects than DSC.

Energy-dependent transition in patterns can test the nature of the superconducting state.

Abstract

We study the effects of single-impurity scattering on the local density of states in the high-$T_c$ cuprates. We compare the quasiparticle interference patterns in three different ordered states: d-wave superconductor (DSC), d-density wave (DDW), and coexisting DSC and DDW (DSC-DDW). In the coexisting state, at energies below the DSC gap, the patterns are almost identical to those in the pure DSC state with the same DSC gap. However, they are significantly different for energies greater than or equal to the DSC gap. This transition at an energy around the DSC gap can be used to test the nature of the superconducting state of the underdoped cuprates by scanning tunneling microscopy. Furthermore, we note that in the DDW state the effect of the coherence factors is stronger than in the DSC state. The new features arising due to DDW ordering are discussed.