Electronic properties of TaAs2 topological semimetal investigated by transport and ARPES

We have performed electron transport and angle-resolved photo-emission spectroscopy ( ARPES) measurements on single crystals of transition metal dipnictide TaAs2 cleaved along the ((2) over bar 01) surface which has the lowest cleavage energy. A Fourier transform of the Shubnikov-de Haas oscillations shows four different peaks whose angular dependence was studied with respect to the angle between magnetic field and the [(2) over bar 01] direction. The results indicate elliptical shape of the Fermi surface cross- sections. Additionally, a mobility spectrum analysis was carried out, which also reveals at least four types of carriers contributing to the conductance (two kinds of electrons and two kinds of holes). ARPES spectra were taken on freshly cleaved ((2) over bar 01) surface and it was found that bulk states pockets at constant energy surface are elliptical, which confirms the magnetotransport angle dependent studies. First-principles calculations support the interpretation of the experimental results. The theoretical calculations better reproduce the ARPES data if the theoretical Fermi level (FL) is increased, which is due to a small n-doping of the samples. This shifts the FL closer to the Dirac point, allowing investigating the physics of the Dirac andWeyl points, making this compound a platform for the investigation of the Dirac andWeyl points in three-dimensional materials.

Automated summary

In this study, electron transport and angle-resolved photo-emission spectroscopy (ARPES) measurements were carried out on single crystals of TaAs2. The results show the elliptical shape of the Fermi surface cross-sections and at least four types of carriers contributing to the conductance. Theoretical calculations support the experimental findings and reveal a small n-doping in the samples, shifting the theoretical Fermi level (FL) closer to the Dirac point.