Wave vector dependent electron-phonon coupling drives charge-density-wave formation in TbTe3

Abstract

We present a high energy-resolution inelastic x-ray scattering investigation of the soft phonon mode in the charge-density-wave system TbTe${}_3$. We analyze our data based on lattice dynamical calculations using density-functional-perturbation-theory and find clear evidence that strongly momentum dependent electron-phonon-coupling defines the periodicity of the CDW superstructure: Our experiment reveals strong phonon softening and increased phonon line widths over a large part in reciprocal space adjacent to the CDW ordering vector $q_{CDW}=(0,0,0.3)$. Further, $q_{CDW}$ is clearly offset from the wave vector of (weak) Fermi surface nesting $q_{FS}=(0,0,0.25)$ and our detailed analysis indicates that electron-phonon-coupling is responsible for this shift. Hence, we can add TbTe${}_3$, which was previously considered as a canonical CDW compound following the Peierls scenario, to the list of distinct charge-density-wave materials characterized by momentum dependent electron-phonon coupling.

References in corpus (4)

• Fermi surface nesting and the origin of Charge Density Waves in metals
• ARPES Study of the Evolution of Band Structure and Charge Density Wave Properties in RTe3 for R = Y, La, Ce, Sm, Gd, Tb and Dy
• Alternative route to charge density wave formation in multiband systems
• Magnetic properties of the charge density wave compounds RTe3, R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm