Regensburg 2022 – wissenschaftliches Programm
MA 17.2: Hauptvortrag
Dienstag, 6. September 2022, 15:30–16:00, H43
From spintronics at limiting temporal and spatial scales in antiferromagnets to an emerging altermagnetic phase — •Tomas Jungwirth — Institute of Physics, Czech Academy of Sciences and University of Nottingham, UK
Magnetically ordered crystals are traditionally divided into two basic phases -- ferromagnetism and antiferromagnetism. In the first part of the talk, we will recall that the ferromagnetic order offers a range of phenomena and existing device applications, while the vanishing net magnetization in antiferromagnets is potentially favorable for temporal and spatial scalability of spintronic devices. In the second part of the talk we will move on to the recent predictions of instances of strong time-reversal symmetry breaking and spin splitting in electronic bands, typical of ferromagnetism, in crystals with antiparallel compensated magnetic order, typical of antiferromagnetism. This apparent fundamental conflict in magnetism is resolved by symmetry considerations that allow us to classify and describe a third basic magnetic phase. Its alternating spin polarizations in both crystal-structure real space and electronic-structure momentum space suggest a term altermagnetism. We will demonstrate that altermagnets combine merits of ferromagnets and antiferromagnets, that were regarded as principally incompatible, and have merits unparalleled in either of the two traditional basic magnetic phases. We will show that they underpin a development of a new avenue in spintronics based on strong non-relativistic spin-conserving phenomena, without magnetization imposed scalability limitations, and with complex logic-in-memory functionalities.