Direct Observation of Large Altermagnetic Splitting in CrSb (100) Thin Film

Abstract Altermagnets represent a newly discovered class of magnetically ordered materials. Among all the candidates, CrSb stands out due to its largest spin splitting energy and highest Néel temperature exceeding 700 K, making it promising for room-temperature spintronic applications. Here we have successfully grown high quality CrSb (100) thin film on GaAs (110) substrate by molecular beam epitaxy. Using angle-resolved photoemission spectroscopy, we successfully obtained the three-dimensional electronic structure of the thin film. Moreover, we observed the emergence of the altermagnetic splitting bands corresponding to the calculated results along the low symmetry paths <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>T</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> – <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>Q</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>P</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> – <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>D</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> . The bands near the Fermi level are only spin splitting bands along the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>P</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> – <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>D</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> direction, with splitting energy reaching as high as 910 meV. This finding provides insights into the magnetic properties of CrSb thin films and paves the way for further studies on their electronic structure and potential applications in spintronics.