Exploring Exotic Electronic States in 2D Transition Metal Dichalcogenides

Possibility to be followed by a PhD with a funding from Doctoral School.

Exploring Exotic Electronic States in 2D Transition Metal Dichalcogenides
Two dimensional (2D) materials have emerged as a fascinating field of research due to their
unique properties that often differ significantly from their bulk counterparts. In the large
familly of 2D materials, transition metal dichalcogenides (TMDs) ave garnered particular
interest as they host a large variety of exotic electronic ground states such as superconductiviy,
mott insulator and charge density wave (CDW). CDW is an electronic phase characterized by a
spatial modulation of the electron density present in some metallic materials, often linked to
the apparition of a bandgap in the electronic spectrum. While CDWs are well-understood in
one-dimensional systems through the Peierls distortion model, their origin in 2D materials
remains less clear. The coupling between CDWs in heterostructures and their interactions with
local perturbation is even more enigmatic.
The primary goal of this internship is to shed light on the interactions between CDWs and
their surrounding environment. Our group has recently shown that CDW can be manipulated by
a local excitation with an STM tip [1] (see Figure 1). Here, we will investigate the coupling
between two TMD materials exhibiting different CDWs and the coupling with atomic-scale
defects, such as strong or weak pinning centers. To achieve this, we will use scanning tunneling
microscopy and spectroscopy (STM/STS) to probe the electronic properties at the atomic scale
in single-layer TMDs and TMD heterostructures.

[1] U. Chazarin et al., Spatially Extended Charge Density Wave Switching by Nanoscale Local
Manipulation in a VTe2 Monolayer, Nano Letters 24, 3470 (2024)