Enhanced quasiparticle dynamics of quantum well states: the giant Rashba system BiTeI and topological insulators

TL;DR

This paper investigates the quasiparticle dynamics of surface states in the giant Rashba semiconductor BiTeI and topological insulators, revealing enhanced scattering processes linked to quantum well states and surface potential effects.

Contribution

It demonstrates that quantum well states are responsible for surface scattering in BiTeI and compares these effects with topological insulators, highlighting differences in symmetry and scattering behavior.

Findings

Surface scattering in BiTeI depends on surface termination and potential shifts.

Quantum well states cause enhanced quasiparticle dynamics with high scattering rates.

Differences in Lorentzian symmetry indicate distinct scattering mechanisms in BiTeI and topological insulators.

Abstract

In the giant Rashba semiconductor BiTeI electronic surface scattering with Lorentzian linewidth is observed that shows a strong dependence on surface termination and surface potential shifts. A comparison with the topological insulator Bi2Se3 evidences that surface confined quantum well states are the origin of these processes. We notice an enhanced quasiparticle dynamics of these states with scattering rates that are comparable to polaronic systems in the collision dominated regime. The Eg symmetry of the Lorentzian scattering contribution is different from the chiral (RL) symmetry of the corresponding signal in the topological insulator although both systems have spin-split surface states.