Nature of the Dirac point magnon gap in the van der Waals Ferromagnet CrSiTe₃

The quasi-two-dimensional, semiconducting ferromagnet CrSiTe₃ is an attractive candidate for spintronics applications and as a candidate to host bosonic topological excitations. Its relatively accessible transition temperature, large magnetic moment and the ability to grow large, clean single crystals makes this an ideal material for study. In this work, we perform detailed neutron scattering measurements of the magnetic excitations near the K-point in the ordered phase to determine the nature of the magnon gap. We find that the existence and magnitude of the gap is highly dependent on the model Hamiltonian and the experimental conditions, and we refine the bounds for the size of the gap.