Researcher in Quantum Materials (M/F)

Job Description

Missions

The primary objective is to experimentally demonstrate the existence of a magnetic moment associated with chiral phonons in structurally chiral and simple, yet non-magnetic, systems. The atomic element tellurium (Te) has been identified as the ideal candidate for this proof of concept. This choice is justified by the simplicity of its crystal structure (3 atoms per unit cell), which limits the number of vibrational branches and thus guarantees excellent resolution of the inelastic neutron scattering signal. The chiral aspect of phonons in Te remains unexplored, even though Raman measurements have shown a degeneracy lifting at the Γ point associated with chiral phonons. By applying the polarized neutron methodology that will be used at the Institut Laue-Langevin (ILL), it will be possible to quantify the induced magnetic moment. Next, the project will focus on the induction of chiral phonons in systems that are not structurally chiral. Indeed, circular vibrations can acquire a chiral character if time-reversal symmetry is broken. This breaking can result from the application of an external field (for example, the application of a magnetic field in PbSnSe) or from the emergence of an internal magnetic order in ferromagnetic systems (such as Co3Sn2S2), leading to the lifting of mode degeneracy and the appearance of chiral phonons. The objective of this part of the program is to study the induction of phonon chirality in such achiral crystals and to understand the underlying microscopic mechanisms. This second part will be carried out on the BIFROST instrument at ESS.

Activity

- Phonon dispersion calculation
- Inelastic neutron scattering experiments at ILL and ESS
- Development of data processing tools for neutron scattering, including instrumental resolution

Your Profil

Skills

Expertise in ab initio DFT modeling (ou Expertise in ab initio DFT calculations)
Expertise in lattice dynamics
Expertise in inelastic neutron scattering

Your Work Environment

The Laboratoire Léon Brillouin (LLB) is a joint research unit (UMR12 – CEA/CNRS) and France's national laboratory for neutron scattering. Its missions include conducting its own research using neutron scattering, constructing, maintaining, and operating instruments at various neutron sources across Europe, as well as training users. Within the laboratory, the New Frontiers in Quantum Materials (NFMQ) group is dedicated to the study and discovery of new quantum states of matter, such as topological magnons, molecular magnetism, frustrated systems, superconductivity, and functional materials. Effectively studying these complex systems often requires multiple experimental techniques, among which neutron scattering plays a central role. In this context, the commissioning of the European Spallation Source (ESS) in 2027 heralds a revolution in the measurement and analysis methods available to researchers. In particular, the BIFROST spectrometer will enable the exploration of quantum materials—for instance, to understand the role of magnetism in superconductors, as well as to measure phonon and magnon spectra in functional materials.

Constraints and risks

Regular travel in France and Sweden
Work in controlled area (ILL)

Compensation and benefits

Compensation

3200

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