Crystal time-reversal symmetry breaking and spontaneous Hall effect in collinear antiferromagnets

• Published in: Science advances Vol. 6; no. 23; p. eaaz8809
• Main Authors: Šmejkal, Libor, González-Hernández, Rafael, Jungwirth, T., Sinova, J.
• Format: Journal Article
• Language: English
• Published: American Association for the Advancement of Science 05.06.2020
• Subjects: Condensed Matter Physics; Materials Science; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aaz8809

Identification of a previously overlooked spontaneous Hall effect mechanism creates opportunities in low-dissipation spintronics. Electrons, commonly moving along the applied electric field, acquire in certain magnets a dissipationless transverse velocity. This spontaneous Hall effect, found more than a century ago, has been understood in terms of the time-reversal symmetry breaking by the internal spin structure of a ferromagnetic, noncolinear antiferromagnetic, or skyrmionic form. Here, we identify previously overlooked robust Hall effect mechanism arising from collinear antiferromagnetism combined with nonmagnetic atoms at noncentrosymmetric positions. We predict a large magnitude of this crystal Hall effect in a room temperature collinear antiferromagnet RuO 2 and catalog, based on symmetry rules, extensive families of material candidates. We show that the crystal Hall effect is accompanied by the possibility to control its sign by the crystal chirality. We illustrate that accounting for the full magnetization density distribution instead of the simplified spin structure sheds new light on symmetry breaking phenomena in magnets and opens an alternative avenue toward low-dissipation nanoelectronics.