Abstract:
Quasiparticle dynamics on the topological surface state of Bi2Se3, Bi2Te3, and superconducting Cu𝑥Bi2Se3 are studied by 7 eV laser-based angle resolved photoemission spectroscopy. We find strong mode couplings in the Dirac-cone surface states at energies of ∼3 and ∼15–20 meV associated with an exceptionally large coupling constant 𝜆 of ∼3, which is one of the strongest ever reported for any material. This result is compatible with the recent observation of a strong Kohn anomaly in the surface phonon dispersion of Bi2Se3, but it appears that the theoretically proposed “spin-plasmon” excitations realized in helical metals are also playing an important role. Intriguingly, the ∼3 meV mode coupling is found to be enhanced in the superconducting state of Cu𝑥Bi2Se3.
Citation:
Kondo, T., Nakashima, Y., Ota, Y., Ishida, Y., Malaeb, W., Okazaki, K., ... & Ando, Y. (2013). Anomalous Dressing of Dirac Fermions in the Topological Surface State<? format?> of Bi 2 Se 3, Bi 2 Te 3, and Cu-Doped Bi 2 Se 3. Physical Review Letters, 110(21), 217601.