Speaker
Description
With a few exceptions, all metallic Transition Metal Dichalcogenides (TMDs), whether in the 2h or 1t polytype, experience instabilities toward a distortion of the underlying lattice (often referred to as a charge density wave). With the advent of 2D materials, it has been shown that these instabilities persist down to the monolayer limit. The resulting effect on the electronic properties can be either small or significant, depending on the magnitude of the displacement of the atoms from their high-symmetry position. We argue that the underlying mechanism is the same in all of them, although in a different regime: from a weak/intermediate strength of the electron-phonon coupling where the fermiology plays a key role and the Peierls instability provides a good starting point for understanding, to a strong coupling regime where the Fermi surface is irrelevant and a local picture of bond formation is more appropriate.
