Evidence for the coexistence of Dirac and massive carriers in a-(BEDT-TTF)2I3 under hydrostatic pressure

TL;DR

This study provides evidence that under hydrostatic pressure, a-(BEDT-TTF)2I3 hosts both high-mobility Dirac and low-mobility massive carriers, confirmed through transport measurements and supported by band structure calculations.

Contribution

It demonstrates the coexistence of Dirac and massive carriers in a-(BEDT-TTF)2I3 under pressure, a novel finding in organic layered compounds.

Findings

Coexistence of Dirac and massive carriers confirmed.

High-mobility Dirac carriers persist under high pressure.

Results align with DFT band structure calculations.

Abstract

Transport measurements were performed on the organic layered compound \aI3 under hydrostatic pressure. The carrier types, densities and mobilities are determined from the magneto-conductance of \aI3 . While evidence of high-mobility massless Dirac carriers has already been given, we report here, their coexistence with low-mobility massive holes. This coexistence seems robust as it has been found up to the highest studied pressure. Our results are in agreement with recent DFT calculations of the band structure of this system under hydrostatic pressure. A comparison with graphene Dirac carriers has also been done.