Chiral Spin Mode on the Surface of a Topological Insulator

Abstract

Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi${}_2$Se${}_3$. We observe a sharp peak at 150 meV in the pseudovector $A_2$ symmetry channel of the Raman spectra. By comparing the data with calculations, we identify this peak as the transverse collective spin mode of surface Dirac fermions. This mode, unlike a Dirac plasmon or a surface plasmon in the charge sector of excitations, is analogous to a spin wave in a partially polarized Fermi liquid, with spin-orbit coupling playing the role of an effective magnetic field.

9 pages, 7 figures, accepted for publication in Phys. Rev. Lett

References in corpus (11)

• Non-Abelian Anyons and Topological Quantum Computation
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• The space group classification of topological band insulators
• Inelastic Light Scattering From Correlated Electrons
• Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator
• Spin-Polarized Surface Resonances Accompanying Topological Surface State Formation
• Chiral spin resonance and spin-Hall conductivity in the presence of the electron-electron interactions
• Collective modes in two- and three-dimensional electron systems with Rashba spin-orbit coupling
• Origin of the low critical observing temperature of the quantum anomalous Hall effect in V-doped (Bi, Sb)2Te3 film
• Faraday rotation due to surface states in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$

Cited by in corpus (15)

• Tuning Inelastic Light Scattering via Symmetry Control in 2D Magnet CrI${}_3$
• Observation of Chiral Surface Excitons in a Topological Insulator Bi${}_2$Se${}_3$
• First-principles calculations of double resonance Raman spectra for monolayer MoTe${}_2$
• Collective spin modes in Fermi liquids with spin-orbit coupling
• Electronic and Vibrational Excitations on the Surface of the Three-Dimensional Topological Insulator Bi${}_2$Te${}_{3-x}$Se${}_x$ (x = 0, 2, 3)
• Spin-orbit interaction enabled electronic Raman scattering from charge collective modes
• Chiral Electronic Excitations in a Quasi-2D Rashba System BiTeI
• Phonon-Induced Collective Modes in Spin-Orbit Coupled Polar Metals
• Spin-Mediated Direct Photon Scattering by Plasmons in BiTeI
• Dirac plasmon polaritons and magnetic modes in topological-insulator nanoparticles
• Chiral electronic excitations and strong electron-phonon coupling to Weyl fermions in the Kagome semimetal Co${}_3$Sn${}_2$S${}_2$
• Resonant Edelstein and inverse-Edelstein effects, charge-to-spin conversion, and spin pumping from chiral-spin modes
• Electronic Raman scattering from 2D metals with broken inversion symmetry
• Many-body correction to the intrinsic anomalous and spin Hall conductivities
• Zero-field spin resonance in graphene with proximity-induced spin-orbit coupling