Exploring Exotic Electronic States in 2D Transition Metal Dichalcogenides

The MPQ laboratory (Laboratoire Matériaux et Phénomènes Quantiques) specializes in the study of frontier quantum materials and novel quantum devices.

The activities of the laboratory span:

- novel materials at the nanoscale: nanocrystals, functionalized nanotubes, multiferroics, 2D materials, etc.

- novel phases of matter: quantum fluids of light, ultrastrong coupling in cavity, unconventional superconductivity, strongly correlated systems, topological phases, etc.

- nano-optical systems: optomechanics, nonlinear nanophotonics, nanoplasmonics, etc.

- quantum engineering and quantum information: quantum optoelectronic devices, quantum photonic circuits, trapped ions, hybrid organic/inorganic devices, surface and interface engineering.

The STM group is devoted to the study of materials at the nanometer scale on surfaces. This includes 2D materials, molecules on surfaces. Our goal is to study and understand the fundamental properties of matter down to the atomic scale, linking a structural analysis with the measurement of the electronic density of states and magnetism.

Internship supervisor: Jérôme Lagoute       

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]. 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.

This project is linked to a CNRS international research project with the National Taïwan University where sample synthesis is mastered. A PhD thesis is expected to start following the internship.

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

Candidates should have a preferential background in material science, surface physics, nanoscience and should have a real interest in experimental physics. Skills/knowledge in scanning tunneling microscopy are prefered.