Quantum oscillations and nontrivial topological properties of layered metal SrAg₄Sb₂

We investigate on the synthesis and physical properties of layered metal SrAg4Sb2 single crystals. The crystals present large unsaturated magnetoresistance up to 2.4 x 10(4)% at T = 1.8 K and B = 28 T. Strong quantum oscillations were observed in both magnetotransport and magnetic torque measurements under high magnetic fields. The analysis of oscillations reveals the existence of multi-bands in this material. Our experimental results and the theoretical calculation suggest that SrAg4Sb2 hosts a nontrivial topological bandgap and should be a topological semimetal candidate.