Using a combination of angle-dependent spectroscopic ellipsometry and angle-resolved photoemission spectroscopy as a function of temperature and supported by first-principles calculations, we reveal a new pair of correlated plasmonic excitations at 1.04 and 1.52 eV and a significant Fermi level shift of 0.12 eV, accompanied by spectral weight transfer in the topological insulator, Bismuth Selenide (Bi2Se3). Interestingly, such a spectral weight transfer over a broad energy range causes a drastic change in the charge-carrier density whereby the contribution of charge-carriers in the bulk starts to rival those in the surface states and Bi2Se3 becomes more uniformly conducting.
- Thomas J. Whitcher
- Mathieu G. Silly
- Andrivo Rusydi
