  Low-dimensional materials are susceptible to electronic instabilities such as
charge density waves (CDWs), originating from a divergence in the Lindhard
electron response function, combined with a finite electron-phonon coupling
strength. In this report, we present a detailed characterisation of the CDW in
the quasi-one-dimensional material CuTe, including (1) direct visualization of
lattice distortion seen with non-contact atomic force microscopy in real space,
(2) the out-of-plane momentum dependency of the CDW gap size of the
quasi-1-dimensional bands, by angle-resolved photoemission spectroscopy, (3)
coherent dynamics of a photoexcited phonon mode seen by time- and
angle-resolved photoemission spectroscopy, with frequency and wavevector q_CDW
corresponding to the soft phonon modes predicted by theory. Furthermore, we
find that the CDW gap closes through a transient band renormalisation. We thus
confirm that, despite the quasi-1D characteristics of CuTe, it hosts inherently
3-dimensional CDWs.
