Large transverse Hall-like signal in topological Dirac semimetal Cd3As2

TL;DR

This study reports a large transverse Hall-like signal in the topological Dirac semimetal Cd3As2, linked to spin-split bands and intrinsic anomalous velocity, revealing new transport phenomena in this material.

Contribution

It uncovers a significant Hall-like signal in Cd3As2 linked to spin-split bands and intrinsic anomalous velocity, supported by experimental and band calculation evidence.

Findings

Observation of a large antisymmetric magnetoresistance in Cd3As2

Splitting of Shubnikov-de Haas oscillations indicating degeneracy lifting

Correlation of the Hall-like signal with spin-split band structure

Abstract

Cadmium arsenide ($\rm Cd_3As_2$) is known for its inverted band structure and ultra-high electron mobility. It has been theoretically predicted and also confirmed by ARPES experiments to exhibit a 3D Dirac semimetal phase containing degenerate Weyl nodes. From magneto-transport measurements in high quality single crystals of $\rm Cd_3As_2$, a small effective mass $m^* \approx$ 0.05 $m_e$ is determined from the Shubnikov-de Haas (SdH) oscillations. In certain field orientations, we find a splitting of the SdH oscillation frequency in the FFT spectrum suggesting a possible lifting of the double degeneracy in accord with the helical spin texture at outer and inner Fermi surfaces with opposite chirality predicted by our \textit{ab initio} calculations. Strikingly, a large antisymmetric magnetoresistance with respect to the applied magnetic fields is uncovered over a wide temperature range in needle crystal of $\rm Cd_3As_2$ with its long axis along [112] crystal direction. It reveals a possible contribution of intrinsic anomalous velocity term in the transport equation resulting from a unique 3D Rashba-like spin splitted bands that can be obtained from band calculations with the inclusion of Cd antisite defects.