Résumé :

Bidimensional electron systems have drawn much attention from the scientific community. In the 1980s the semiconductor heterojunctions have been discovered and led to integer and fractional quantum Hall effect. In 2004 it was the discovery of graphene with its Dirac fermion physics where electrons behave as massless particles that produced a deep impact. In this talk, I will address an original Dirac system : the organic salt -(BEDT-TTF)2I3 under hydrostatic pressure. This system presents a quasi-2D electronic transport with tilted Dirac cones in its band structure. I will start by showing evidence of the coexistence between Dirac and massive fermions as well as analysing the consequences on the mobility due to the nature of the carriers. I will follow by the study of quantum oscillations (Shubnikov-de-Haas oscillations). I will highlight their unconventional characteristics at high magnetic field, which is interpreted as an evidence of distorted (non-perfect) Dirac cones. Then I will address the role of surface doping of crystals probed by photoemission which leads to a 1D Luttinger liquid transport in contrast with the 2DEG of the bulk. Finally, I will present the possible studies that can be carried out in the near future on this system.

Contact : matteo.dastuto@neel.cnrs.fr