Quantitative measurement of temperature-dependent quasiparticle scattering of the topological surface states in Bi₂Se₃

The quasiparticle scattering processes of the topological surface state (TSS) in three-dimensional topological insulators (TIs) have a vital effect on many-body interaction and potential applications of topological materials. In this work, we have performed high-resolution temperature-dependent angle-resolved photoemission spectroscopy (ARPES) of 3D strong TI Bi₂Se₃. With ab initio simulation, we have analyzed the temperature dependence of the electronic structure and lifetime broadening of TSS, which are closely associated with the quasiparticle scattering process, i.e., electron-phonon coupling and spin-dependent scattering. We show that, at low temperature (7 K), the spin-dependent electron scattering facilitates the anisotropic scattering rate of TSS. Conversely, at room temperature (300 K), the electron-phonon coupling dominates the contribution to the scattering rate. The scattering rate increases with temperature and turns uniform in momentum space due to the temperature dependence of quasiparticle scattering. The quantitative study of temperature-dependent scattering rates in TSS is crucial to understanding the topological property and transport mobility of Dirac fermions for fundamental studies and potential applications.