Uncovering hidden Fermi surface instabilities through visualizing unconventional quasiparticle interference in CeTe3

TL;DR

This study visualizes unconventional quasiparticle interference in CeTe3, revealing hidden Fermi surface instabilities linked to shadow bands and matrix element effects, which influence electronic properties and magnetic phases in low-dimensional materials.

Contribution

It uncovers the dominant scattering mechanisms involving shadow bands and highlights their role in Fermi surface instabilities and magnetic behavior in CeTe3.

Findings

Predominant scattering between original and shadow bands at 4 K

Suppressed scattering within original bands at Fermi energy

Shadow bands' spectral weight influences electronic properties

Abstract

The charge density wave (CDW) state is a widespread phenomenon in low-dimensional metals/semimetals. The spectral weight of the associated folded bands (shadow bands) can be an intriguing trigger leading to additional Fermi surface instability and unexplored phase transitions. The rare earth tri-telluride CeTe3 exhibits a single CDW stabilized below ~400 K and antiferromagnetism below ~3 K. The distinct periodicities between the Te-square net, the CeTe block layer, and the CDW give rise to rich shadow band formations. In this work, we reveal the predominant scattering between the original and shadow bands at 4 K, with the scattering within the original bands being relatively suppressed at Fermi energy. This unconventional quasi-particle scattering collectively underscores the vital role of the shadow bands' spectral weight and the hidden matrix element effect, which are crucial for controlling electronic properties in this system. Furthermore, our finding points to the existence of rich and unexplored Fermi surface instabilities, which potentially play a role in controlling the nature of long-range antiferromagnetism at lower temperatures in the presence of finite charge-spin interaction.