Giant octupole moment in magnetic multilayers

Abstract

Multipole moments serve as order parameters for characterizing higher-order magnetic effects in momentum space, providing a framework to describe diverse magnetic responses by extending the concept of magnetism. In this letter, we introduce a methodology to quantitatively determine the multipole moment contributions in anomalous Hall effect through angle-dependent anomalous Hall current, with explicit incorporation of discrete crystal symmetries. Our technique uniquely enables the investigation of octupole contribution in non-periodic systems, particularly at interfaces and surfaces. Typically, in (Ag${}_2$Fe${}_5$)${}_n$ multilayers with quantum-well-engineered $k$-point selectivity, we observe an octupole-dominated anomalous Hall effect in conventional ferromagnetic materials, through first-principles calculations. These results fundamentally challenge the existing theoretical understanding of the anomalous Hall effect, showing that even the conventional contribution arises not only from the dipole moment (net magnetization). Furthermore, we establish practical control over the octupole contribution through two distinct approaches: interface engineering and magnetic ordering reconfiguration, opening new possibilities for manipulating higher-order transport effects.

References in corpus (11)

• Progress and prospects in magnetic topological materials
• Electrical Manipulation of a Topological Antiferromagnetic State
• Cluster multipole theory for anomalous Hall effect in antiferromagnets
• Multivariable Scaling for the Anomalous Hall Effect
• Gate-controllable magneto-optic Kerr effect in layered collinear antiferromagnets
• Direct Method for Calculating Temperature-Dependent Transport Properties
• Calculating spin transport properties from first principles: spin currents
• Anomalous-Hall Neel textures in altermagnetic materials
• Unified First-Principles Study of the Anomalous Hall Effect Based on Exact Muffin-Tin Orbitals
• On the angular dependence of anomalous Hall current
• Pseudo anomalous Hall effect in semiconductors and semimetals: A classical perspective