Elastic properties at the charge density wave phase transitions in TbTe₃, ErTe₃ and HoTe₃

ABSTRACT

Rare earth tritelluride TbTe${}_3$, ErTe${}_3$ and HoTe${}_3$ exhibit two successive charge density wave phase transitions $T_{\mathrm{C}\mathrm{D}\mathrm{W}1}$ and $T_{\mathrm{C}\mathrm{D}\mathrm{W}2}$. The transition to the incommensurate phase at $T_{\mathrm{C}\mathrm{D}\mathrm{W}2}$ is reflected in the longitudinal elastic stiffness components $C_{11}$ and $C_{33}$. In the incommensurate phase below $T_{\mathrm{C}\mathrm{D}\mathrm{W}2}$ the longitudinal stiffness components $C_{11}$, $C_{33}$ are augmented by a contribution from quartic anharmonic interaction with the onset of the incommensurate ordering. The temperature dependences of the elastic constants $C_{11}$, $C_{33}$ are shown to follow a $T^2$ law. The mechanism for the lower CDW phase transition is significantly different from that at the upper CDW phase transition.

KEYWORDS:

• Structural phase transition
• charge density waves
• elastic constants
• Rare Earth Tritellurides

Disclosure statement

No potential conflict of interest was reported by the author(s).