Abstract
Cadmium arsenide (Cd3As2) 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 Cd3As2, a small effective mass m* ≈ 0.05 me 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 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 Cd3As2 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.
Highlights
The upper inset shows the optical image of a 6 mm-long needle crystal of Cd3As2. (c) Optical images of needle A and B, showing triangular and rectangle cross-sections, where the corresponding (112) and (200) planes are illustrated in the upper panel. (d) Temperature dependence of the resistivity for needle A and needle B, showing similar metallic behavior
For the phase stabilized at the lowest temperature, the Cd vacancies could be arranged orderly within a large tetragonal cell composed of corner-sharing CdAs4 tetrahedral units
The symmetry of Cd3As2 generated at the lowest temperature has been controversially indexed with either noncentrosymmetric space group I41cd33 or I41/acd with centrosymmetry34
Summary
The pure oscillatory component of resistivity for needle B is shown, where two SdH frequencies of 20.4 and 27.3 Tesla and m* = 0.0232 me were determined. Due to the broken centrosymmetry by the Cd antisites, the spin texture on the inner and outer Fermi surfaces revolve in the opposite direction as shown in the upper inset of Fig. 4(c) similar to a Rashba-like band-splitting.
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