2026/11/06(Fri) 10:30 -12:00 五樓第一會議室 5F, 1st Meeting Room
Title
Cross-correlation phenomena in altermagnets
Speaker
Prof. Hitoshi Seo (RIKEN Center for Emergent Matter Science, Japan)Abstract
Altermagnets are a type of antiferromagnet that exhibit an alternating spin order with a wave vector q = 0; in the limit where the spin-orbit
interaction is zero, the net magnetization is canceled out. The simplest case is a system with two sublattices within a unit cell, in which up spins
and down spins are ordered, respectively. If these sublattices are not connected by translation or inversion operations, the system breaks macroscopic
time-reversal symmetry and exhibits characteristic cross-correlation phenomena not observed in ordinary antiferromagnets [1].
In this talk, we will discuss the phenomena expected in altermagnetic systems and their microscopic mechanisms: 1. non-relativistic spin splitting and
spin current generation [2], 2. the anomalous Hall effect [3], and 3. the piezomagnetic effect [4]. Although there has already been extensive research
on each of these, we will specifically demonstrate —using models of typical strongly correlated organic compounds— that the conditions for their
emergence and the key factors involved differ. Furthermore, we will point out the similarity between the structure of molecular dimers in organic
systems and the lattice distortion known as the GdFeO₃-type in inorganic perovskite-type compounds [5]. If time permits we will briefly introduce our
recent progresses on interplay with quantum phenomena such as superconductivity [6] and quantum Hall effect [7].
[1] As a review: M. Naka, Y. Motome, H. Seo, npj Spintronics 3, 1 (2025).
[2] M. Naka et al., Nat. Communications 10, 4305 (2019).
[3] M. Naka et al., Phys. Rev. B 102, 075112 (2020).
[4] M. Naka, Y. Motome, T. Miyazaki, H. Seo, J. Phys. Soc. Jpn. 94, 083702 (2025).
[5] M. Naka, Y. Motome, H. Seo, Phys. Rev. B 103, 125114 (2021); Phys. Rev. B 106, 195149 (2022).
[6] S. Sumita, M. Naka, H. Seo, Phys. Rev. Research 5, 043171 (2023); Phys. Rev. B 112, 144510 (2025).
[7] M. Naka, S. Sumita, Y. Motome, H. Seo, preprint (arXiv:2608.12124).
Language
演講語言 (Language): in English