Tunable Dirac Fermion Dynamics in Topological Insulators

Abstract

Three-dimensional topological insulators are characterized by insulating bulk state and metallic surface state involving relativistic Dirac fermions which are responsible for exotic quantum phenomena and potential applications in spintronics and quantum computations. It is essential to understand how the Dirac fermions interact with other electrons, phonons and disorders. Here we report super-high resolution angle-resolved photoemission studies on the Dirac fermion dynamics in the prototypical Bi2(Te,Se)3 topological insulators. We have directly revealed signatures of the electron-phonon coupling and found that the electron-disorder interaction dominates the scattering process. The Dirac fermion dynamics in Bi2(Te3−xSex) topological insulators can be tuned by varying the composition, x, or by controlling the charge carriers. Our findings provide crucial information in understanding and engineering the electron dynamics of the Dirac fermions for fundamental studies and potential applications.

Spatially resolved Landau level spectroscopy of the topological Dirac cone of bulk-typeSb2Te3(0001): Potential fluctuations and quasiparticle lifetime

“…The fact that time-resolved ARPES data at B = 0 T find relaxation times of about τ = 1 ps at E D − E F = 0 − 100 meV [76,77], which would correspond to ∆E = /τ = 0.7 meV indicates that either the B field and the related localization of electrons or the presence of the STM tip might change the scattering rates significantly. Notice that the lifetimes observed by the fit of the line widths of ARPES data [78,79] are typically even shorter than the ones observed by LL spectroscopy [41,43] and, thus, in stronger discrepancy to the time-resolved data [80,81]. This is most likely due to disorder averaging, i.e.…”

Fanoq-reversal in topological insulator Bi2Se3

“…The topic is important from the fundamental point, as well as for potential practical applications of topological insulators. The problem has been studied with a variety of experimental techniques, including optical spectroscopy [2,3,4], Angle Resolved Photoemission Spectroscopy [5,6,7], time-domain THz spectroscopy [8] and helium scattering [9]. The importance of phonons has also been studied theoretically [10].…”

Dynamics of domain-wall Dirac fermions on a topological insulator: A chiral fermion beam splitter

“…[40][41][42][43] Compositional tuning of Dirac fermion electronic structure has been demonstrated for BiTl(S 1x Se d ) 2 , Bi 2 (Te 3−x Se x ). 44,45 Placed on a substrate, electric contacts have been made to the TI.…”