Large negative magnetoresistance beyond chiral anomaly in topological insulator candidate CeCuAs<sub>2</sub> with spin-glass-like behavior

Large negative magnetoresistance (NMR), an important property for spintronics, requires experimental realization owing to the lack of suitable structural motifs. Herein, a remarkable NMR of up to -15% under 9 T at 2 K is demonstrated in a 112-type topological insulator candidate CeCuAs₂ single crystal containing an As square net. Due to the presence of Dirac points coming from both the As square net and Ce�CCu�CAs layer in the paramagnetic state of CeCuAs₂, the possibility of chiral anomaly is examined and eliminated by investigating magnetoresistance (MR) with different magnetic field configurations and angle-dependant MR, which show no specific restriction on the configurations under the applied magnetic fields. Upon investigation of the anisotropic magnetism, a spin-glass-like behavior with T_f ~ 4.5 K is observed in CeCuAs₂, indicating that the large NMR could be attributed to the spin-dependent scattering induced by the possible spin-glass state. Hall resistivity exhibits a multiband feature and hole-dominated transport properties, corresponding well with the calculated band structure. This study not only offers a new building block for large NMR but also serves as a guide for the investigating the interplay among transport properties, topology, and magnetism, and it is expected to broaden the research on spintronics.