Quantum oscillations and nontrivial topological properties of layered metal SrAg4Sb2

Abstract

We investigate on the synthesis and physical properties of layered metal SrAg4Sb2 single crystals. The crystals present large unsaturated magnetoresistance up to 2.4 × 104% 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.

3D – 2D Crossover and Phase Shift of Beats of Quantum Oscillations of Interlayer Magnetoresistance in Quasi-2D Metals

“…Below we show how this phase inversion during the 3D -2D crossover is described by analytical formulas. The understanding of this MQO phase inversion is helpful for experimental studies of the Berry phase using MQO measurements [38][39][40][41].…”

δ‐Bonding and Spin‐Orbit Coupling Make SrAg4Sb2 a Topological Insulator

“…In this study we will examine features of transition metal bonds that lead to topological bands in the Zintl phase SrAg 4 Sb 2 , shown in Figure 1. SrAg 4 Sb 2 was synthesized in 2012 and later identified as a topological material by computational studies [20–23] . It belongs to a family of layered pnictides notable for their transport properties: SrAg 4 As 2 and EuAg 4 Sb 2 show complex magnetism and magnetoresistance; [24–26] EuSn 2 As 2 and EuIn 2 As 2 are topological insulators; [27,28] and EuCd 2 As 2 is one of the few magnetic Weyl semimetals [29] .…”

“…SrAg 4 Sb 2 was synthesized in 2012 and later identified as a topological material by computational studies. [20][21][22][23] It belongs to a family of layered pnictides notable for their transport properties: SrAg 4 As 2 and EuAg 4 Sb 2 show complex magnetism and magnetoresistance; [24][25][26] EuSn 2 As 2 and EuIn 2 As 2 are topological insulators; [27,28] and EuCd 2 As 2 is one of the few magnetic Weyl semimetals. [29] Metal-metal bonds control their structures; Sn 2+ in EuSn 2 As 2 has a stereochemical lone pair, so the Sn atoms are staggered to minimize repulsions, while EuIn 2 As 2 has formal In 2+ which stabilizes its one 5s electron by forming In-In bonds.…”