Collective plasmon excitations in a helical electron liquid on the surface of strong three-dimensional topological insulator are considered. The properties and internal structure of these excitations are studied. Due to spin-momentum locking in helical liquid on a surface of topological insulator, the collective excitations should manifest themselves as coupled charge- and spin-density waves.
@article{arxiv.1107.4695,
title = {Spin-plasmons in topological insulator},
author = {D. K. Efimkin and Yu. E. Lozovik and A. A. Sokolik},
journal= {arXiv preprint arXiv:1107.4695},
year = {2012}
}