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 Néel transition temperature of around 700 K. Molecular beam epitaxy is used to synthesize CrSb (0001) thin films with thicknesses ranging from 10 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 bulk-type, 3D momentum-dependent band splitting of up to 0.7 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 µ10 nm thin film limit at room temperature.
| Original language | English |
|---|---|
| Journal | Advanced Materials |
| DOIs | |
| State | Accepted/In press - 2025 |
Funding
This project was primarily supported by the Penn State Two‐Dimensional Crystal Consortium‐Materials Innovation Platform (2DCC‐MIP) under NSF Grant No. DMR‐2039351 (SS, YO, AR, NS). Additional support was provided a seed grant from the Penn State MRSEC Center for Nanoscale Science via NSF award DMR 2011839 (SI, AT, NS, BY), including use of the low‐temperature transport facilities (DOI: 10.60551/rxfx‐9h58). AT was supported in part by NSF‐SITE: PHYS‐2349159. The authors also acknowledge NSF Grant No. DMR‐2309431 (SG, KAM). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC (DMR‐2011401). We acknowledge support from the University of California, Santa Barbara (UCSB) National Science Foundation (NSF) Quantum Foundry through Q‐AMASE‐i Program via Award No. DMR‐1906325 (PC, WY, CJP). The research reported here made use of the shared facilities of the Materials Research Science and Engineering Center(MRSEC) at UC Santa Barbara: NSFDMR–2308708 (PC, WY, CJP). This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DEAC02‐05CH11231 (AF). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. DOE, Office of Science, Office of Basic Energy Sciences under Contract No. DEAC02‐76SF00515 (MH, DL). Certain commercial products or company names are identified here to describe our study adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the products or names identified are necessarily the best available for the purpose.
Keywords
- ARPES
- MBE
- altermagnet
- antiferromagnet
- neutron reflectivity