Study of single crystalline SrAgSb and SrAuSb semimetals

TL;DR

This study investigates the electronic properties of single crystalline SrAgSb and SrAuSb semimetals through experimental measurements and DFT calculations, revealing their topological nature and magnetoresistance behavior.

Contribution

The paper provides the first detailed experimental and theoretical analysis of SrAgSb and SrAuSb, identifying SrAgSb as a trivial semimetal and SrAuSb as a Dirac semimetal.

Findings

SrAgSb is a topologically trivial, compensated semimetal.

SrAuSb is a topologically non-trivial Dirac semimetal.

Both compounds exhibit non-saturating magnetoresistance.

Abstract

Given renewed interest in the electronic properties of semimetallic compounds with varying degrees of spin orbit coupling we have grown single crystals of SrAgSb and SrAuSb, measured their temperature and field dependent electrical resistivity and magnetization and performed density functional theory (DFT) band structure calculations. Magnetization measurements are consistent with a diamagnetic host with a small amount of local moment bearing impurities. Although the residual resistivity ratio (RRR) for all samples studied was relatively low, ranging between 2.4 and 3.4, the compounds had non-saturating magnetoresistance (MR), reaching values of $\sim$ 17% and $\sim$ 70% at 4 K and 9 T for SrAgSb and SrAuSb respectively. Band structure calculations, using the experimentally determined Wyckoff positions for the Sr, Ag/Au, and Sb atoms, show that whereas SrAgSb is a topologically trivial, but compensated, semimetal; SrAuSb is a topologically non-trivial, Dirac semimetal.