Laser angle-resolved photoemission as a probe of initial statekzdispersion, final-state band gaps, and spin texture of Dirac states in theBi2Te3topolog

Abstract

We have obtained angle-resolved photoemission (ARPES) spectra from single crystals of the topological insulator material Bi2Te3 using a tunable laser spectrometer. The spectra were collected for eleven different photon energies ranging from 5.57 to 6.70 eV for incident light polarized linearly along two different in-plane directions. Parallel first-principles, fully relativistic computations of photo-intensities were carried out using the experimental geometry within the framework of the one-step model of photoemission. A reasonable overall accord between theory and experiment is used to gain insight into how properties of the initial and final state band structures as well as those of the topological surface states and their spin-textures are reflected in the laser-ARPES spectra. Our analysis reveals that laser-ARPES is sensitive to both the initial state kz dispersion and the presence of delicate gaps in the final state electronic spectrum.

Three-dimensional nature of the band structure of ZrTe5 measured by high-momentum-resolution photoemission spectroscopy

“…This behavior suggests that the spectrum is modulated by the structure of final states 32 , and therefore cannot be understood solely in the context of a well-defined initial state dispersion. More detailed calculations involving electron final-states are required to fully understand this complexity 33 .…”

Spin-dependent electron–radiation interaction

“…Photoemission has been regarded as an inert probe of the intrinsic electronic structure. The spin-resolved photoemission of topological insulators [16][17][18][19][20], bulk Rashba semiconductors [21], metal alloys [22,23], and noble metals [24] has however indicated a clear dependence on the photon of a different energy and polarization.…”