Charge-density-wave state induced by structural distortion in heavy-fermion compounds Ce$_3$M$_4$Sn$_{13}$ (M=Co, Ru, Rh)

TL;DR

This paper investigates the structural distortion and charge density wave (CDW) formation in Ce$_3$M$_4$Sn$_{13}$ compounds, using XRD simulations to understand how CDW influences crystal structure and diffraction patterns.

Contribution

It introduces a novel XRD analysis method that models structural distortions without symmetry constraints, revealing the origin of CDW in these heavy-fermion compounds.

Findings

Distortion occurs on specific crystallographic planes.

Charge density wave causes significant changes in diffraction intensities.

Simulation accurately reproduces low-temperature structural features.

Abstract

In previous reports a structural transition from a cubic phase of Yb$_3$Rh$_4$Sn$_{13}$ - type to the superlattice variant has been reported at $\sim160$ K for a series of skutterudite-related Ce$_3$M$_4$Sn$_{13}$ compounds, where M=Co, Ru or Rh. We have simulated the low-temperature XRD diffraction patterns of the distorted unit cell using written for that purpose DISTorX program. The method proposed here for x-ray diffraction analysis obtains the XRD patterns from the atomic positions and allows to investigate crystal structure without imposed symmetry operations. We have indicated crystallographic plane where distortion occurs and explained possible origin of CDW in these materials. We have also shown that distortion caused by the charge density wave leads to significantly changes of the intensity of diffraction lines.