Identify the dominant component responsible for SCCLA’s anomalous properties

Identify which constituent element(s) or structural component(s) of sulfur–copper codoped lead apatite (SCCLA) dominate the experimentally observed anomalous behaviors, including the magnetic hysteresis/diamagnetic response up to approximately 250 K and the linear-in-temperature resistivity, by determining whether the lead apatite framework, the copper–sulfur sublattice, or the alkali cations are primarily responsible.

Background

The paper reports anomalous transport and magnetic behaviors in sulfur–copper codoped lead apatite (SCCLA), including a linear-in-temperature resistivity indicative of a strange-metal phase and diamagnetic hysteresis loops up to about 250 K. To probe which component governs these behaviors, the authors synthesize a lead-free compound (S3) and observe similar features, suggesting that lead may not be essential.

This motivates a direct unresolved question about the identity of the component(s) that dominate the observed anomalies, with candidates including the copper–sulfur sublattice within the apatite channels and the alkali ions, while lead may mainly contribute structural robustness.