Two-dimensional transport and strong spin orbit interaction in SrMnSb₂

Breaking the time-reversal symmetry (TRS) or inversion symmetry (IS) of a Dirac semimetal can realize Weyl state. IS breaking Weyl semimetal (WSM) has been experimentally realized in TaAs family, while the TRS breaking WSM is relatively rare. Recently, the nonstoichiometric SrMnSb2 is reported to be a long-sought TRS-breaking Weyl semimetal with canted antiferromagnetic order. Here we report the first pulse high field (up to 60T) magneto transport study for this material. Clear Shubnikov-de Haas Oscillations were resolved at relatively low magnetic field (around 4T), revealing a quasi 2D Fermi surface. We observed the development of quantized plateaus in R_xy which we interpreted as the bulk Quantum Hall. Moreover, angular dependent Zeeman splitting reveals an anisotropic g factor. The presence of the anisotropic g factor together with the formation of the beating pattern in oscillation reveal strong spin-orbit interaction in the material. Our observation provides more insights of this material system and calls for further investigations into the composition related topological property evolution.