Spin waves in doped graphene with in-plane magnetic fields*

Plasmonics in graphene and related 2D materials has attracted much interest, with many prospects for novel applications. However, the dynamics of collective spin excitations and spin waves in 2D materials has been much less explored. Here, we study the spin-wave excitations of itinerant electrons in doped graphene in the presence of in-plane magnetic fields. We calculate the spin-wave dispersions using time-dependent density-functional methods within a standard tight-binding approach. Dynamical exchange-correlation effects are treated using the Singwi-Tosi-Land-Sjolander (STLS) approach, generalized for systems with noncollinear spins.