题目：Spin transport in p-wave and altermagnets
报告人：Aurélien Manchon
邀请人：杨洪新
时间：2025年10月17日（周五）上午10点
地点：紫金港校区海纳苑8幢215报告厅
摘要：
In traditional condensed matter textbooks, magnetic materials are classified into three main categories: ferromagnets, ferrimagnets, and antiferromagnets. Since antiferromagnets exhibit a magnetic order with no overall magnetization, one naturally expects no spin polarization in the band structure. In recent years, the discovery of spin-orbit torque in “PT-symmetry broken” antiferromagnets (e.g., CuMnAs, Mn2Au) and anomalous Hall effect in noncollinear antiferromagnets (Mn3Sn, MnNiN) has launched an unprecedented effort to revisit this classification, leading to the discovery of new forms of antiferromagnets with spin-polarized bands. At the moment (things move fast), two such classes gather much attention: the so-called altermagnets [1] and p-wave magnets [2]. The former presents a symmetric spin polarization in the Brillouin zone, whereas the latter presents an antisymmetric one. This presentation focuses on the transport properties of these new systems.
In this lecture , after a general overview of the topic, I will discuss the transport properties of d-wave altermagnets, deriving the phenomenological spin diffusion equation and applying it to magnetic textures [3]. I will also consider the role of electron-magnon interactions and show that charge currents can be accompanied by magnon current displaying the so-called “magnetic spin Hall effect” [4]. Then, I will move on to p-wave magnets. Using group symmetry analysis, model calculations, and realistic simulations on selected compounds, I will study spin-polarization in the band structure and demonstrate that current-driven torque is possible [5]. Importantly, none of the effect discussed here involve spin-orbit coupling.
[1] Yuan et al., Giant momentum-dependent spin splitting in centrosymmetric low-Z antiferromagnets, Physical Review B 102, 014422 (2020); Smejkal et al., Emerging Research Landscape of Altermagnetism, Physical Review X 12, 040501 (2022).
[2] Hellenes et al., Unconventional p-wave magnets, arXiv:2309.01607; Brekke et al., Minimal Models and Transport Properties of Unconventional p-Wave Magnets, Physical Review Letters 133, 236703 (2024).
[3] Manchon, unpublished
[4] Sourounis, Manchon, Efficient generation of spin currents in altermagnets via magnon drag, Physical Review B 111 (13), 134448
[5] Gonzalez-Hernandez et al., Non-relativistic torque and Edelstein effect in non-collinear magnets, Nature Communications, 15, 7663 (2024).
个人简介：
Aurélien Manchon received his Ph.D. degree in 2007 from University Joseph Fourier at SPINTEC laboratory in France. He worked as a postdoctoral fellow from 2008 to 2009 at University of Missouri-Columbia and University of Arizona-Tuscon in USA. Afterwards, he became an Assistant, then Associate Professor of Materials Science and Engineering at the King Abdullah University of Science and Technology (KAUST), in Saudi Arabia (2009-2019). He is currently a Professor of Physics in the Centre Interdisplinaire de Nanoscience de Marseille (CINaM) at Aix-Marseille University (AMU) since 2019. His research interest spans from quantum transport and spin-orbit coupling in condensed matter to chiral magnetism, antiferromagnets, and ultrafast spin dynamics.
