Tuning magnetism and transport via interatomic distance in a p -wave magnet candidate Mn5Si3

Abstract

Unconventional antiferromagnets, including altermagnets and p-wave magnets, can exhibit spin splitting and anomalous transport with vanishing net magnetization, providing a promising platform for antiferromagnetic spintronics. However, microscopic control of their magnetic states and anomalous Hall responses remains insufficiently understood. Here, focusing on a p-wave magnet candidate Mn5Si3, we investigate three types of Mn5Si3 single crystals to clarify how interatomic distances regulate the candidate p-wave magnetic state and anomalous Hall effect. Despite having indiscernible chemical compositions and undergoing similar structural-transition sequences upon cooling, Rietveld refinements show that distinct changes in the average atomic environments, particularly in the Mn–Mn distances, modify the competing Mn–Mn exchange interactions and redistribute Mn moments, leading to different low-temperature magnetic responses and field-induced magnetic transitions. Consequently, the anomalous Hall conductivity is tuned to approximately −162, −125, and 59 S/cm in the three samples, respectively, showing pronounced changes in both magnitude and sign. Theoretical calculations further indicate that the anomalous Hall response is not simply determined by magnetization but arises from the coupled modulation of magnetic configuration and electronic structure by structural degrees of freedom. These results identify average Mn–Mn interatomic distance as a key microscopic parameter for controlling anomalous Hall transport in the p-wave magnet candidate Mn5Si3 and further suggest interatomic distance engineering as an effective route for manipulating unconventional antiferromagnetic spintronic responses.