Raman spectra and dimensional effect on the charge density wave transition in CdTe_3

摘要

The studies of the dimensional effect on the charge density wave (CDW) transition have attracted a lot of attention since the rise of 2D materials. In this paper, we synthesize high-quality single-crystal GdTe3, a member of the layered rare-earth metal tritelluride family with CDW transitions, and systematically study the temperature-dependent Raman spectra of bulk and few-layer GdTe3. Combining with first-principle calculations, the CDW and phonon Raman peaks are distinguished and characterized. We demonstrate that the CDW order can be enhanced in few-layer GdTe3, and the CDW transition temperature increases from 377 K to 431 K as the thickness reduces from the bulk to 10 nm. We speculate that this enhancement of the CDW order in the GdTe3 thin layer is likely due to the chemical pressure release. Our studies demonstrate that the dimensionality provides a valuable tuning parameter for manipulating the CDW properties of GdTe3.