Charge density wave formation inR2Te5(R=Nd, Sm, and Gd)

Abstract

The rare earth $(R)$ tellurides ${R}_{2}{\mathrm{Te}}_{5}$ have a crystal structure intermediate between that of $R{\mathrm{Te}}_{2}$ and $R{\mathrm{Te}}_{3}$, consisting of alternating single and double Te planes sandwiched between $R\mathrm{Te}$ block layers. We have successfully grown single crystals of ${\mathrm{Nd}}_{2}{\mathrm{Te}}_{5}$, ${\mathrm{Sm}}_{2}{\mathrm{Te}}_{5}$, and ${\mathrm{Gd}}_{2}{\mathrm{Te}}_{5}$ from a self-flux and we describe here 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 wave vectors. 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.