Title: Altermagnetism: band structures and its potential for device applications
일시: 2025년 3월 25일(화), 17시
Speaker: Changyoung Kim (Seoul National University)
Abstract:
The third class of magnetism, dubbed altermagnetism, has been a recent hot topic in the field of magnetism. Altermagnets have characteristics of both ferro- (FM) and antiferro-magnetism (AFM): spin-split bands (thus broken time-reversal symmetry) and zero net magnetization. These traits are not only important from a fundamental scientific perspective but also for spintronic applications. Topological features such as Weyl nodes in altermagnets are discussed in recent studies.
For spintronic applications, altermagnets are expected to have the merits of both FM and AFM—strong signal and high operating speed, respectively. In this colloquium talk, I will introduce altermagnets, covering their basic properties and potential applications. I will first explain the fundamentals of altermagnetism, including collinear AFM (zero net magnetization) and spin-split bands (time-reversal symmetry breaking). Then, I will describe the origin of spin splitting based on symmetry analysis and microscopic mechanisms.
Experimental verification of altermagnetism is inherently difficult due to the zero net magnetization, but the spin-split bands can be measured in certain cases. I will introduce our recent ARPES (Angle-Resolved Photoemission Spectroscopy) work on an altermagnet MnTe. The ARPES data show split bands that merge into a single band above the Néel temperature, strongly indicating the magnetic origin of the splitting. If time permits, I will also briefly discuss recent studies on the device applications of altermagnets, including RuO₂ magnetic tunnel junctions and switching behavior in MnTe.