Effect of Chemical Substitutions on the Extreme Magnetoresistance and Topological State of PtSn₄

It has recently been discovered that the extreme magnetoresistive material PtSn₄ [1] has a novel topological state, with the observation of Dirac node arcs in ARPES measurements [2]. This material has a quasi-two dimensional crystal structure composed of an edge-sharing network of PtSn₈-square antiprisms. We study the effect of chemical substitutions on the electronic properties of PtSn₄ via two pathways: (i) we consider the effect of replacing platinum by gold, giving AuSn₄ and (ii) we consider the effect of substituting tin with lead, giving PtPb₄. In the first substitution the crystallographic properties are left unaltered (ABAB stacking, orthorhombic) but in the second there is a minor structural modification (AAA stacking, tetragonal). Both materials superconduct at low temperatures with T_c = 2.5 K for AuSn₄ and T_c = 2.8 K for PtPb₄. In this talk, we will present our studies of the electronic and topological properties of these compounds and comment on their relationship to PtSn₄.

[1] Mun et al., Phys. Rev. B 85 035135 (2012).
[2] Wu et al., Nature Physics 12 667–671 (2016).