Large unconventional anomalous Hall effect in a chiral antiferromagnetic semiconductor

Combination of structural chirality and magnetism always plays a critical role of nontrivial electronic transport properties, nurturing unconventional contribution to the anomalous Hall effect (UAHE), in which the non-colinear or non-coplanar magnetic structure promised by chiral lattice or finite spin-chirality rising from geometric frustration takes the responsibility. Here we report a remarkable phenomenon of UAHE in an antiferromagnetic (AFM) semiconductor EuIr₂P₂, which possesses a potential helical AFM ground state promised by natural chiral crystalline structure. EuIr₂P₂ displays an anisotropic negative magnetoresistance as well as a surprising UAHE below and above Néel temperature (T_N1 = 5.2 K), exhibiting large values of unconventional anomalous Hall resistivity reach to 3 mΩ cm at 2 K and 1 mΩ cm at 10 K. These behaviors can be qualitatively understood via a skew scattering mechanism originated from the promised helical magnetic structure below T_N1 and finite spin-chirality rising from AFM spin fluctuation above T_N1. Our results illuminate the path for comprehending the strong interaction between expected novel spin texture produced by chiral lattice and hopping carriers in AFM semiconductors.