We report an ambient-pressure Dirac electron (DE) state in a new organic conductor, α-(BETS)2AuCl2 (BETS = bis(ethylenedithio)tetraselenafulvalene). This salt exhibits characteristic transport properties, including large positive in-plane and anomalous negative interlayer magnetoresistance. These signatures closely resemble the high-pressure DE states of α-(ET)2I3 (ET = bis(ethylenedithio)tetrathiafulvalene). First-principles calculations including spin-orbit coupling identify the electronic state as a quasi-three-dimensional massive Dirac semimetal with residual Fermi pockets. This discovery provides a valuable platform for exploring bulk Dirac fermions without the complexity of high-pressure measurements.
@article{arxiv.2602.21398,
title = {Ambient-Pressure Organic Dirac Electron State in $\alpha$-(BETS)$_2$AuCl$_2$},
author = {Takuya Kobayashi and Kazuyoshi Yoshimi and Aoto Nishimoto and Shinji Michimura and Hiromi Taniguchi},
journal= {arXiv preprint arXiv:2602.21398},
year = {2026}
}
Comments
5 pages, 4 figures; Supplemental Material: 6 pages, 2 figures, accepted for publication in J. Phys. Soc. Jpn. (Letter)