Determination of the crystal field splitting energy in Cd3As2 using magnetooptics

TL;DR

This study precisely measures the crystal field splitting energy in Cd3As2 using magnetooptical spectroscopy, enhancing understanding of its band structure and topological properties.

Contribution

The paper introduces a combined magnetooptical spectroscopy approach to accurately determine the crystal field splitting in Cd3As2, a key parameter for its topological characteristics.

Findings

Crystal field splitting δ is positive and 15±5 meV.

Band structure details, including Dirac node positions, are clarified.

Splitting into Weyl nodes under magnetic field is better understood.

Abstract

Symmetry considerations are of extreme importance to the topological properties of crystals. A crystal field splitting {\delta} yields Dirac nodes near the Brillouin zone center in Cd3As2, but its value has yet to be determined with precision. We study the band structure of Cd3As2 using magnetooptical infrared spectroscopy measurements on epilayers with low carrier density grown by molecular beam epitaxy. By combining angular dependent cyclotron resonance with Landau level spectroscopy measurements in the Faraday geometry, we determine that {\delta} is positive and equal to 15+/-5 meV in Cd3As2. Our results lead to a more accurate knowledge of the details of the band structure of this Dirac semimetal such as the position its Dirac nodes in momentum space and their splitting into Weyl nodes under a magnetic field.