Unidirectional Electronic Structure in the Parent State of Iron-Chalcogenide Superconductor Fe$_{1+\delta}$Te

TL;DR

This study reveals a unidirectional electronic structure in Fe$_{1.07}$Te, the parent compound of iron-chalcogenide superconductors, linked to magnetic and orbital orders, observed via scanning tunnelling microscopy and spectroscopy.

Contribution

It provides the first direct observation of unidirectional electronic structures in the parent state of iron-chalcogenide superconductors, connecting electronic, magnetic, and orbital orders.

Findings

Unidirectional electronic pattern observed along the a-axis.

Pattern persists within -200 to +130 meV energy range.

Pattern aligns with underlying magnetic and orbital orders.

Abstract

We use scanning tunnelling microscopy and spectroscopy to explore the electronic structure of Fe$_{1.07}$Te which is the parent compound of the iron-chalcogenide superconductors. A unidirectional electronic structure with a period of $a_{0}$ (where $a_{0}$ is the lattice constant) along the a-axis is observed. The unidirectional pattern is visible within an energy range from approximately -200 to +130 meV. Since the direction of the unidirectional electronic structure coincides with those of the underlying antiferromagnetic and the predicted orbital orders, it is presumable that the observed unidirectional structure is closely tied to these orders and is peculiar to the parent state in iron-based superconductors.