Altermagnetic band splitting in 10 nm epitaxial CrSb thin films

Published

May 1, 2025

Author(s)

Sandra Santhosh, Yongxi Ou, Paul Corbae, Wilson Yanez-Parreno, Supriya Ghosh, Alexei Fedorov, Makoto Hashimoto, Donghui Lu, Christopher Jensen, Julie Borchers, Alexander Grutter, Timothy Charlton, Anthony Richardella, K. A. Mkhoyan, Christopher Palmstrom, Nitin Samarth

Abstract

Altermagnets are a newly identified family of collinear antiferromagnets with a momentum-dependent spin-split band structure of non-relativistic origin, derived from spin-group symmetry-protected crystal structures. Among candidate altermagnets, CrSb is attractive for potential applications because of a large spin-splitting near the Fermi level and a high N´eel transition temperature of around 700 K. We use molecular beam epitaxy to synthesize CrSb (0001) thin films with thicknesses ranging from 10 nm to 100 nm. Structural characterization, using reflection high energy electron diffraction, scanning transmission electron microscopy, and X-ray diffraction, demonstrates the growth of epitaxial films with good crystallinity. Polarized neutron reflectometry shows the absence of any net magnetization, consistent with antiferromagnetic order. In vacuo angle resolved photoemission spectroscopy (ARPES) measurements probe the band structure in a previously unexplored regime of film thickness, down to 10 nm. These ARPES measurements show a three-dimensional momentum-dependent band splitting of up to 1 eV with g-wave symmetry, consistent with that seen in prior studies of bulk single crystals. The distinct altermagnetic band structure required for potential spin-transport applications survives down to the ∼ 10 nm thin film limit at room temperature.

Citation

Physical Review Materials

Pub Type

Journals

Keywords

altermagnet, molecular beam epitaxy, ARPES

Citation

Santhosh, S. , Ou, Y. , Corbae, P. , Yanez-Parreno, W. , Ghosh, S. , Fedorov, A. , Hashimoto, M. , Lu, D. , Jensen, C. , Borchers, J. , Grutter, A. , Charlton, T. , Richardella, A. , Mkhoyan, K. , Palmstrom, C. and Samarth, N. (2025), Altermagnetic band splitting in 10 nm epitaxial CrSb thin films, Physical Review Materials (Accessed June 13, 2025)