Measurement of Two Low-Temperature Energy Gaps in the Electronic Structure of Antiferromagnetic USb2 Using Ultrafast Optical Spectroscopy

TL;DR

This study uses ultrafast optical spectroscopy to identify two distinct low-temperature energy gaps in USb2, revealing complex electronic interactions involving f-electron hybridization and magnon effects.

Contribution

It provides the first direct measurement of two low-temperature energy gaps in USb2 and elucidates their origins related to f-electron hybridization and magnon-induced band renormalization.

Findings

Two charge gaps open below 45 K.

One gap results from f-electron hybridization.

The second gap involves magnon-related band renormalization.

Abstract

Ultrafast optical spectroscopy is used to study the antiferromagnetic f-electron system USb2. We observe the opening of two charge gaps at low temperatures (<45 K), arising from renormalization of the electronic structure. Analysis of our data indicates that one gap is due to hybridization between localized f-electron and conduction electron bands, while band renormalization involving magnons leads to the emergence of the second gap. These experiments thus enable us to shed light on the complex electronic structure emerging at the Fermi surface in f-electron systems.