Altermagnetic Band Splitting in 10 nm Epitaxial CrSb Thin Films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• Altermagnets are a novel class of collinear antiferromagnets.
• They possess a unique momentum-dependent band splitting originating from crystal symmetry.
• Chromium antimonide (CrSb) is a promising altermagnet candidate due to its high Néel temperature and significant spin-splitting.

Purpose of the Study:

• To synthesize and characterize CrSb (0001) thin films.
• To investigate the survival of altermagnetic properties in thin films.
• To explore the potential of CrSb for spintronic applications.

Main Methods:

• Epitaxial growth of CrSb (0001) thin films using molecular beam epitaxy.
• Structural characterization via reflection high energy electron diffraction, scanning transmission electron microscopy, and X-ray diffraction.
• Probing electronic band structure using in-vacuo angle-resolved photoemission spectroscopy (ARPES).

Main Results:

• Epitaxial CrSb films with good crystallinity were successfully grown.
• Absence of net magnetization confirmed antiferromagnetic order via polarized neutron reflectometry.
• ARPES measurements revealed a bulk-type, 3D momentum-dependent band splitting up to 0.7 eV with g-wave symmetry, persisting down to 10 nm thickness.

Conclusions:

• The distinct altermagnetic band structure of CrSb is maintained in thin films.
• This property survives down to the 10 nm limit at room temperature.
• CrSb thin films are viable candidates for future spintronic devices.