Linear dispersion of Dirac fermions in (Cd_1–x–yZn_xMn_y)₃As₂, х+y = 0.2, у = 0.02, 0.04, 0.06, 0.08 solid solutions

Abstract

Based on the results of the Shubnikov-de Haas oscillations study in single-crystalline diluted magnetic semiconductors (Cd1−x−yZnxMny)3As2 (CZMA) with х + y = 0.2 and Mn content (у = 0.02, 0.04, 0.06, 0.08) at temperatures T = 4.2 to 30 K and magnetic fields B = 0 to 12 T under hydrostatic pressure p = 0 and 10 kbar, the values of the phase shift β, indicating the existence of the Berry phase in all samples were determined. Thickness of two-dimensional surface topological nanolayers in CZMA (х + y = 0.2) single crystals was defined. The rise in Mn concentration led to an increase in the concentration of charge carriers in the 2D surface layers n 2D and a decrease in its mobility μ 2D. The reduced cyclotron mass m с (0)/m 0, depending on the Fermi wave vector k F , experimentally observed from the Shubnikov-de Haas oscillations, which was in a good agreement with the prediction theory of linear dependence and experimental results in topological insulator single crystals Bi2Se3 indicated that Dirac fermions were present in a diluted magnetic semiconductor CZMA system with х + y = 0.2. The damping of the Shubnikov-de Haas oscillations for pressures p = 0 and 10 kbar in the CZMA sample (х + y = 0.2; y = 0.2) was found to be associated with an amplitude decrease by spin splitting (Zeeman effect). From the analysis of experimental data, the effective Lande factor g = 7.63 and 7.87 and the band gap Δ =35.3 and 9.7 meV at p = 0 and 10 kbar, respectively, were obtained.