Direct imaging of incommensurate wave pockets in the charge-density-wave state of LaTe2
1 Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences - Beijing 100190, China
2 Collaborative Innovation Center of Quantum Matter - Beijing 100084, China
Received: 12 April 2016
Accepted: 20 June 2016
We herein report the study of the atomic structure for a fully incommensurate CDW in LaTe2 using Cs-corrected scanning transmission electron microscopy (STEM). It is directly revealed for the first time that the atomic displacements adopt an incommensurate wave-pocket structure along each Te chain. This pocket structure has a long periodicity determined by the CDW incommensurability. We can use the sinusoidal waves as the first-order approximation to characterize the atomic motions within the pocket pattern, which can yield atomic displacements in good agreement with the theoretical model commonly used for studying CDW. These facts demonstrate that the incommensurate pocket patterns should be an essential structural nature in the CDW states and play a critical role for developing the mechanism of the CDW transitions.
PACS: 71.45.Lr – Charge-density-wave systems / 61.44.Fw – Incommensurate crystals / 61.05.-a – Techniques for structure determination
© EPLA, 2016