Collective excitations on a surface of topological insulator

Dmitry K. Efimkin, Yurii E. Lozovik, Alexey A. Sokolik

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47 Citations (Scopus)


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 particles 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.

Original languageEnglish
Article number163
Pages (from-to)1-27
Number of pages27
JournalNanoscale Research Letters
Publication statusPublished - 8 Mar 2012
Externally publishedYes

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