Charge density wave formation in $R_{2}$Te$_{5}$ ($R$=Nd, Sm and Gd)

TL;DR

This study reports the discovery of charge density wave formation in rare earth tellurides $R_2$Te$_5$ ($R$=Nd, Sm, Gd), revealing complex superlattice patterns linked to Fermi surface sheets from Te layers.

Contribution

First evidence of charge density waves in $R_2$Te$_5$ compounds with detailed analysis of superlattice structures and electronic origins.

Findings

Charge density waves are present in Nd$_2$Te$_5$, Sm$_2$Te$_5$, and Gd$_2$Te$_5$.

Superlattice patterns involve multiple wavevectors.

Wave vectors are associated with specific Fermi surface sheets.

Abstract

The rare earth ($R$) tellurides $R_2$Te$_5$ have a crystal structure intermediate between that of $R$Te$_2$ and $R$Te$_3$, consisting of alternating single and double Te planes sandwiched between $R$Te block layers. We have successfully grown single crystals of Nd$_2$Te$_5$, Sm$_2$Te$_5$ and Gd$_2$Te$_5$ from a self flux, and describe here the first evidence for charge density wave formation in these materials. The superlattice patterns for all three compounds are relatively complex, consisting at room temperature of at least two independent wavevectors. Consideration of the electronic structure indicates that to a large extent these wave vectors are separately associated with sheets of the Fermi surface which are principally derived from the single and double Te layers.