TY - JOUR
T1 - Chiral Spin Mode on the Surface of a Topological Insulator
AU - Kung, H. H.
AU - Maiti, S.
AU - Wang, X.
AU - Cheong, S. W.
AU - Maslov, D. L.
AU - Blumberg, G.
N1 - Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/9/27
Y1 - 2017/9/27
N2 - Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi2Se3. We observe a sharp peak at 150 meV in the pseudovector A2 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.
AB - Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi2Se3. We observe a sharp peak at 150 meV in the pseudovector A2 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.
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U2 - 10.1103/PhysRevLett.119.136802
DO - 10.1103/PhysRevLett.119.136802
M3 - Article
C2 - 29341673
AN - SCOPUS:85030171472
SN - 0031-9007
VL - 119
JO - Physical Review Letters
JF - Physical Review Letters
IS - 13
M1 - 136802
ER -