We report experimental measurements and theoretical analysis of Shubnikov-de Haas (SdH) oscillations in a Dirac cone system: the a-(BEDT-TTF)2I3 organic metal under hydrostatic pressure. The measured SdH oscillations reveal anomalies at high magnetic fields B where the 1/B oscillations periodicity is lost above 7 T. We interpret these unusual results within a theoretical model that takes into account intrinsic distortions of the a-(BEDT-TTF)2I3 Dirac cones such as a parabolic particle-hole asymmetric correction. Others possible causes, such as a cone tilting or a Zeeman effect, are carefully ruled out. The observations are consistent among a-(BEDT-TTF)2I3 samples with different Fermi levels.
@article{arxiv.1711.00039,
title = {Aperiodic quantum oscillations of particle-hole asymmetric Dirac cones},
author = {E. Tisserond and J. N. Fuchs and M. O. Goerbig and P. Auban-Senzier and C. Meziere and P. Batail and Y. Kawasugi and M. Suda and H. M. Yamamoto and R. Kato and N. Tajima and M. Monteverde},
journal= {arXiv preprint arXiv:1711.00039},
year = {2017}
}