Magnetic excitations in the normal and nematic phases of iron pnictides

TL;DR

This paper theoretically investigates magnetic excitations in iron pnictides, revealing how their structure and anisotropy differ between normal and nematic phases, with distinct energy evolution in spin and orbital scenarios.

Contribution

It provides a comparative analysis of magnetic excitations in spin and orbital nematic scenarios, highlighting their different energy-dependent anisotropic behaviors.

Findings

Normal state MEs transition from diamond to square-like structures with energy.

Nematic phases show anisotropic MEs due to C4 symmetry breaking.

Spin nematic scenario maintains anisotropy at high energies, orbital nematic reduces it at low energies.

Abstract

In this paper, we study theoretically the behaviors of the magnetic excitations(MEs) in the normal and nematic phases of iron pnictides. The normal state MEs exhibit commensurability to diamond and to square-like structure transition with the increase of energy. This structure transition persists in the spin and orbital scenarios of nematic phases, although the MEs show anisotropic behaviors due to the C4 symmetry breaking induced by the nematic orders. The MEs exhibit distinct energy evolution behaviors between the spin and orbital scenarios of nematicity. For the spinnematic scenario, the anisotropy of the MEs persists up to the high energy region. In contrast, for the orbital-nematic scenario, it reduces dramatically in the low energy region and is negligible in the high energy region. These distinct behaviors of the MEs are attributed to the different origins between the spin and orbital scenarios of nematic orders.