Effect of dimensionality on sliding charge density waves. The case of the quasi-two dimensional TbTe$_3$ system probed by coherent x-ray diffraction

TL;DR

This study investigates how the dimensionality affects charge density wave behavior in the quasi-two-dimensional TbTe$_3$ system, revealing unique deformation and reordering phenomena under current, with implications for room-temperature charge transport.

Contribution

It provides the first observation of bulk CDW behavior in a quasi-two-dimensional system with collective charge transport at room temperature.

Findings

CDW remains undeformed below threshold current I$_S$

Above I$_S$, CDW rotates and reorders by motion

No phase shifts occur below I$_S$, slow variations above

Abstract

We report on sliding Charge Density Wave (CDW) in the quasi two-dimensional TbTe$_3$ system probed by coherent x-ray diffraction combined with {\it in-situ} transport measurements. We show that the non-Ohmic conductivity in TbTe$_3$ is made possible thanks to a strong distortion of the CDW. Our diffraction experiment versus current shows first that the CDW remains undeformed below the threshold current I$_S$ and then suddenly rotates and reorders by motion above threshold. Contrary to quasi-one dimensional systems, the CDW in TbTe$_3$ does not display any phase shifts below I$_S$ and tolerates only slow spatial variations of the phase above. This is a first observation of CDW behavior in the bulk in a quasi-two dimensional system allowing collective transport of charges at room temperature.