Quasiparticle scattering interference in iron pnictides: A probe of the origin of nematicity

TL;DR

This paper compares quasiparticle interference patterns in iron pnictides under magnetic and orbital nematicity scenarios, revealing distinct energy-dependent features that can help identify the origin of nematicity.

Contribution

It provides a detailed analysis of QPI patterns in different nematic scenarios, proposing a method to distinguish magnetic from orbital nematicity in iron pnictides.

Findings

QPI patterns show a dimer structure aligned with SDW order in magnetic scenario.

In orbital scenario, QPI patterns undergo a {c0}/2 rotation with energy increase.

Distinct QPI features can serve as probes for nematicity origin.

Abstract

In this paper, we investigate the quasiparticle scattering interference(QPI) in the nematic phase of iron pnictides, based on the magnetic and orbital scenarios of nematicity, respectively. In the spin density wave(SDW) state, the QPI pattern exhibits a dimer structure in the energy region of the SDW gap, with its orientation along the ferromagnetic direction of the SDW order. When the energy is increased to be near the Fermi level, it exhibits two sets of dimers along the same direction. The dimer structure of the QPI patterns persists with the decrease of the SDW correlation length in the magnetic driven nematic phase, although it tends to merge together for the scattering patterns with energies close to the Fermi level. While in the orbital scenario, the QPI patterns exhibit a dimer structure in a wide energy region. It undergoes a {\pi}/2 rotation with the increasing of energy, which is associated with the inequivalent energies of the two Dirac nodes induced by the orbital order. These distinct features may be used to probe or distinguish two kinds of scenarios of the nemeticity.