Imaging the Néel vector switching in the monolayer antiferromagnet MnPSe3 with strain-controlled Ising order

• Published in: Nature nanotechnology Vol. 16; no. 7; pp. 782 - 787
• Main Authors: Ni, Zhuoliang, Haglund, A. V., Wang, H., Xu, B., Bernhard, C., Mandrus, D. G., Qian, X., Mele, E. J., Kane, C. L., Wu, Liang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-07-2021; Nature Publishing Group
• Subjects: 639/301/119/2795; 639/301/119/997; 639/766/119/1001; Anisotropy; Antiferromagnetism; Chemistry and Materials Science; Ising model; Magnetic fields; Materials Science; Monolayers; Nanotechnology; Nanotechnology and Microengineering; Perturbation; Phase transitions; Second harmonic generation; Spintronics; Switching
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/s41565-021-00885-5

Antiferromagnets are interesting materials for spintronics because of their faster dynamics and robustness against perturbations from magnetic fields. Control of the antiferromagnetic order constitutes an important step towards applications, but has been limited to bulk materials so far. Here, using spatially resolved second-harmonic generation, we show direct evidence of long-range antiferromagnetic order and Ising-type Néel vector switching in monolayer MnPSe
3
with large XY anisotropy. In additional to thermally induced switching, uniaxial strain can rotate the Néel vector, aligning it to a general in-plane direction irrespective of the crystal axes. A change of the universality class of the phase transition in the XY model under uniaxial strain causes this emergence of strain-controlled Ising order in the XY magnet MnPSe
3
. Our discovery is a further ingredient for compact antiferromagnetic spintronic devices in the two-dimensional limit.
Antiferromagnets are interesting materials for fast spintronics applications, but control of the antiferromagnetic order has been limited to bulk materials so far. Now, uniaxial strain is shown to align the Néel vector in MnPSe
3
down to the monolayer limit.