Postdoctoral Researcher in Tunable Nanophononics in van der Waals Heterostructures (M/F)

Job Description

Missions

Acoustic phonons are usually regarded as a source of unwanted effects in electronics, optoelectronics, and quantum technologies. However, recent advances in phonon engineering have demonstrated that these excitations can be exploited to transport information and energy in the ballistic, diffusive, and hydrodynamic regimes. The control of acoustic excitations in nanostructured systems lies at the heart of a new research field: nanophononics. Nevertheless, beyond a few GHz, there are still no standard transducers capable of efficiently controlling these acoustic vibrations, and most experiments rely on optical techniques that strongly depend on the electronic structure of the investigated samples.

In van der Waals heterostructures, this electronic structure can be tuned by modifying the angular alignment between stacked two-dimensional materials, which can dramatically alter their fundamental properties. Remarkable examples include the recent observation of strongly correlated states and intrinsic superconductivity in twisted bilayer graphene, as well as the in situ modification of graphene's band structure through crystallographic alignment with hexagonal boron nitride. These phenomena have given rise to the emerging research field known as twistronics.

In this postdoctoral project, we aim to bridge twistronics and nanophononics. To achieve this goal, we will develop an original approach based on dynamically rotatable heterostructures capable of spatially modulating the electronic density (moiré patterns) and thereby tuning the system's ability to act as a transducer for acoustic phonon generation. We will investigate how crystal-axis alignment influences coherent and incoherent phonon generation mechanisms using advanced Raman and Brillouin scattering techniques, picosecond acoustics pump–probe spectroscopy, and electronic transport measurements.

Activity

Design, fabricate, and optimize twisted van der Waals heterostructures as well as related phononic and electronic devices using micro/nanofabrication and 2D material transfer techniques.
Perform the electrical characterization of the developed devices (electronic transport, gated measurements, dynamical response, and temperature dependence) in order to investigate the influence of twist angle and interlayer coupling.
Develop and implement ultrafast pump–probe spectroscopy and Brillouin scattering experiments to study coherent phonons and the elastic properties of the heterostructures.
Investigate the interplay between electronic, mechanical, and acoustic properties in van der Waals materials, particularly in correlated phases and moiré structures.
Contribute to the analysis of experimental results, the modeling of the observed phenomena, and the scientific dissemination of the project through publications and international presentations.

Your Profil

Skills

This position involves the design, fabrication, and electronic and optical investigation of devices based on van der Waals materials. The postdoctoral researcher will develop expertise in ultrafast optical characterization, Raman/Brillouin scattering, nanofabrication techniques, electronic transport, and electrical measurements on 2D materials.

The candidate should have a strong background in at least one of the following areas: quantum mechanics, van der Waals materials, nanofabrication, electronic transport, nanomechanics, materials science, or photonics. A strong interest in experimental work, physical analysis of results, and interdisciplinary approaches is expected.

Your Work Environment

The postdoctoral researcher will carry out their activities within the Quantum Optics in Semiconductor nanoStructures (GOSS) group and the PHYsics and technology of NANOstructures and quantum systems (PHYNANO) group at the Centre de Nanosciences et de Nanotechnologies.

The C2N is a joint research unit of the CNRS and Université Paris-Saclay. It brings together more than 120 researchers, as well as 80 engineers, technicians, and administrative staff members. The laboratory also hosts a cleanroom technological facility covering more than 2900 m².

Constraints and risks

Use of lasers

Compensation and benefits

Compensation

Between €2,991.58 and €4,756.76 gross per month

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions