Transport evidence of the three-dimensional Dirac semimetal phase in doped $\alpha$-Sn grown by molecular beam epitaxy

TL;DR

This study demonstrates the existence of a three-dimensional Dirac semimetal phase in phosphorus-doped $ ext{α}$-Sn films grown by molecular beam epitaxy, using quantum transport measurements to reveal key topological properties.

Contribution

It provides the first transport evidence of the 3D Dirac semimetal phase in doped $ ext{α}$-Sn, including Fermi surface characterization and chiral anomaly observation.

Findings

Observation of Shubnikov-de Haas oscillations below 30 K

Confirmation of a nontrivial Berry phase

Detection of negative magnetoresistance attributed to chiral anomaly

Abstract

We report the quantum transport properties of the $\alpha$-Sn films grown on CdTe (001) substrates by molecular beam epitaxy. The $\alpha$-Sn films are doped with phosphorus to tune the Fermi level and access the bulk state. Clear Shubnikov-de Haas oscillations can be observed below 30 K and a nontrivial Berry phase has been confirmed. A nearly spherical Fermi surface has been demonstrated by angle-dependent oscillation frequencies. In addition, the sign of negative magnetoresistance which is attributed to the chiral anomaly has also been observed. These results provide strong evidence of the three-dimensional Dirac semimetal phase in $\alpha$-Sn.