Yuan Yan, Zhi-Min Liao, XiaoxingKe, Gustaaf Van Tendeloo, Qinsheng Wang, Dong Sun,Wei Yao, Shuyun Zhou, Liang Zhang, Han-Chun Wu, and Da-Peng Yu State Key Laboratory for Mesoscopic Physics, Department of Physics and International Center for Quantum Materials, Peking University, Beijing 100871, P. R. China.

Collaborative Innovation Center of Quantum Matter, Beijing, P. R. China

EMAT (Electron Microscopy for Materials Science), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium

Department of Physics, Tsinghua University, Beijing 100084, P. R. China

School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China

King Saud University, Riyadh, 11451, Saudi Arabia

Thephotothermoelectric effect in topologicalinsulator Bi2Se3nanoribbons is studied. The topologicalsurface states are excited to be spin-polarized by circularlypolarized light. Because the direction of the electron spin islocked to its momentum for the spin-helical surface states, thephotothermoelectric effect is significantly enhanced as theoriented motions of the polarized spins are accelerated by thetemperature gradient. The results are explained based on the microscopic mechanisms of a photon induced spin transitionfrom the surface Dirac cone to the bulk conduction band. Theas-reported enhanced photothermoelectric effect is expected to have potential applications in a spin-polarized power source.