2011/10/18 by D. K. Efimkin, Yu. E. Lozovik, A. A. Sokolik · 1 citation
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1186/1556-276x-7-163
published as Nanoscale Research Letters 7, 163 (2012) · 9 pages, 6 figures
arxiv created 2011/10/18 · arxiv updated 2012/07/10
We study collective excitations in a helical electron liquid on a surface of three-dimensional topological insulator. Electron in helical liquid obeys Dirac-like equation for massless particless and direction of its spin is strictly determined by its momentum. Due to this spin-momentum locking, collective excitations in the system manifest themselves as coupled charge- and spin-density waves. We develop quantum field-theoretical description of spin-plasmons in helical liquid and study their properties and internal structure. Value of spin polarization arising in the system with excited spin-plasmons is calculated. We also consider the scattering of spin-plasmons on magnetic and nonmagnetic impurities and external potentials, and show that the scattering occurs mainly into two side lobes. Analogies with Dirac electron gas in graphene are discussed.