PhD student for a PhD about experimental exploration of unusual magnetic phases in rhombohedral multilayer graphene (M/F)

Job Description

Thesis Subject

-Twisted multi-layered stacks of graphene have attracted a very strong interest these last years, in part because of the very rich phase diagram at low temperature, displaying many transitions to highly correlated topological electronic states. Recently, similar correlated phases with exotic order parameters were also found in natural graphene multilayers, in portions with a rhombohedral (ABC) stacking rather than the more common bernal (ABA) stacking, see Figure below with a trilayer.
One such phase is an intriguing ordered magnetic phase in which the magnetic moments are not electronic spin but loop currents. So far this unusual phase has only been indirectly revealed through transport measurements, which are insensitive to the sign of the magnetic moment with respect to the applied field. Therefore it is not known if the response is diamagnetic or ferromagnetic, an essential question to elucidate the nature of this new kind of phase transition.
To determine whether this phase is diamagnetic or ferromagnetic as well as its competition with other correlated phases (superconductivity, charge orders etc..), we propose to use the powerful method developed in our group, based on exquisitely sensitive magneto-resistive sensors especially suited to 2D materials whose orbital currents depend on the carrier density (tuned by controlling an electrostatic gate). With this method we have recently observed the anomalous diamagnetism of graphene at the Dirac point as well as the paramagnetism on van Hove singularities (Vallejo et al. Science 2021, Physical Review letters 2023, PhD thesis 2023). The PhD thesis will investigate the orbital magnetism of rhombohedral multilayer graphene using this technique, over the full phase diagram by varying the chemical potential, magnetic field and temperature. We expect these experiments to bring essential information for the understanding of this new quantum state.

Your Work Environment

The Laboratory of Solid State Physics (LPS) is a joint research unit (UMR 8502) of Université Paris-Saclay and the CNRS. It is affiliated with the CNRS Institute of Physics and the 28th section of the National Council of Universities (CNU). The LPS is a member of the Friedel-Jacquinot Federation, a coordination structure for physics research on the Moulon plateau in Orsay (Île-de-France).
It brings together around one hundred researchers and faculty members—both experimentalists and theorists—while research activities are supported by approximately sixty engineers, technicians, and administrative staff.
Each year, the laboratory hosts a large number of undergraduate and graduate students—including many PhD candidates—as well as postdoctoral researchers and visiting scientists. The laboratory covers a wider range of topics than its name suggests, aiming to address the full diversity of condensed matter physics. Research activities are organized around three main themes, each involving a similar number of scientists:
• Novel electronic states of matter
• Physical phenomena in reduced dimensions
• Soft matter and the physics-biology interface
The first theme encompasses both experimental and theoretical studies on the properties of systems characterized by strong electronic correlations; these systems exhibit remarkable properties and unconventional electronic states, such as superconductivity, magnetism, metal-insulator transitions, and more.
The second theme covers activities falling under the broad umbrella of "nanosciences." Here, the focus is on fundamental properties that emerge when an object's dimensions approach certain characteristic length scales (such as coherence length, mean free path, etc.).
The third theme extends the concept of "soft matter" to include biological systems. Topics range from complex systems to living tissues, and from liquid crystals to foams, as well as polymers and granular systems. These physics studies lie at the interface of physical chemistry and biology.
The research will be conducted within the Mesoscopic Physics group at the Laboratory of Solid State Physics (CNRS-UMR 8502).
Your work environment
Remote work: remote work arrangements and allowances
Annual leave and RTT (reduced working time) days: 44 days
Transport: subsidized commuting costs (75% coverage) and a sustainable mobility allowance of up to €300
Support for parents: access to daycare spots, co-funded CESU vouchers and holiday vouchers, contribution to before- and after-school care costs, allowance for parents of children with disabilities, and subsidies for activities (leisure centers, holiday camps, school trips, etc.)
Training: provided upon starting and throughout your career
Onboarding: support during the initial settling-in period
Employee benefits: subsidized health insurance, staff dining facilities, sports and leisure activities, discounted tickets, etc.

Compensation and benefits

Compensation

2300 € gross monthly

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