Giant exchange splitting in the electronic structure of A-type 2D antiferromagnet CrSBr

Authors:
  • MWMatthew D. Watson
    Matthew D. Watson
  • SASwagata Acharya
    Swagata Acharya
  • JNJames E. Nunn
    James E. Nunn
  • LNLaxman Nagireddy
    Laxman Nagireddy
  • DPDimitar Pashov
    Dimitar Pashov
  • MRMalte Rösner
    Malte Rösner
  • MSMark van Schilfgaarde
    Mark van Schilfgaarde
  • NWNeil R. Wilson
    Neil R. Wilson
  • CCCephise Cacho
    Cephise Cacho
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Abstract
We present the evolution of the electronic structure of CrSBr from its antiferromagnetic ground state to the paramagnetic phase above T_N=132 K, in both experiment and theory. Low temperature angle-resolved photoemission spectroscopy (ARPES) results are obtained using a novel method to overcome sample charging issues, revealing quasi-2D valence bands in the ground state. The results are very well reproduced by our QSGŴ calculations, which further identify certain bands at the X points to be exchange-split pairs of states with mainly Br and S character. By tracing band positions as a function of temperature, we show the splitting disappears above T_N. The energy splitting is interpreted as an effective exchange splitting in individual layers in which the Cr moments all align, within the so-called A-type antiferromagnetic arrangement. Our results lay firm foundations for the interpretation of the many other intriguing physical and optical properties of CrSBr.