We investigate collective spin excitations of graphene electrons with short-ranged interactions and subject to the external Zeeman magnetic field. We find that in addition to the familiar Silin spin wave, a collective spin-flip excitation that reduces to the uniform precession when the wave's momentum approaches zero, the magnetized graphene supports another collective mode visible in the transverse spin susceptibility: a collective spin-current mode. Unlike the Silin wave, this mode is not dictated by the spin-rotational symmetry but rather owns its existence to the pseudo-spin structure of the graphene lattice. We find the new collective excitation to become sharply defined in a finite interval of wave's momenta, the range of which is determined by the interaction and the magnetization.
@article{arxiv.2312.16782,
title = {Collective spin oscillations in a magnetized graphene sheet},
author = {M. Agarwal and O. A. Starykh and D. A. Pesin and E. G. Mishchenko},
journal= {arXiv preprint arXiv:2312.16782},
year = {2024}
}