Structural stability and compressibility behaviour of rare-earth ditellurides under pressure

Abstract Quasi-two dimensional rare-earth ditellurides ( R Te 2 ) have gained recent attention due to their pressure-induced charge density wave formation. In this study, the structural stability of R Te 2 compounds (CeTe 2 , PrTe 1.9 and NdTe 2 ) are investigated under high pressure using in situ x-ray diffraction technique and CeTe 2 is additionally examined by first-principles calculations. R Te 2 samples are synthesized by non-isothermal isopiestic method. The ambient tetragonal phase of R Te 2 compounds is preserved up to the highest pressure studied. Bulk moduli of R Te 2 compounds have been estimated and found to show an increasing trend along the rare-earth series. R Te 2 compounds exhibited anisotropic compression along different crystallographic axes, with c axis being more compressible. Anomalous c axis compression is observed in NdTe 2 . This is understood in terms of Nd-Te bond behaviour along the c axis.