Zeeman splitting and quantum-limit magnetoresistance anomaly in the topological insulator β - A g 2 Se

The nontrivial bulk states of topological insulators open avenues for comprehending and harnessing topological phases. Here, the authors demonstrate \ensuremath{\beta}-Ag${}₂$Se as a topological insulator by uncovering exceptional transport properties linked to the bulk states, supported by theoretical calculations. The observation of notable Shubnikov--de Haas oscillations and Zeeman splitting reveals a Land\'e $g$-factor of approximately 10. The longitudinal magnetoresistance exhibits two anomalous dips in the quantum limit, attributed to forbidden backscattering, providing further affirmation of the strong topological insulator characteristics in this compound.