Postdoc: Spin Dynamics and Transport in Magnetic Topological Insulator
Paris
Description of the offer :
Three-dimensional Topological insulator (TI) have attracted tremendous interest due to the existence of two very different states in a single material: a gapped bulk band and gapless Dirac fermion surface states protected by time-reversal symmetry. The goal of this project is to explore spin properties, in TI and particularly magnetic topological insulators (MTI). The experimental study will focus on two TI families : (1) well known TIs such as Sb2Te3 or Bi2Se3 with one single Dirac cone; (2) Topological crystalline insulators (TCI) like SnTe, with four Dirac cones. Derived MTI compounds, obtained by Cr or Mn-doping will be also studied. The objectives will be to study and quantify, in different TIs: (i) the spin polarization dynamics; (ii) the carrier relaxation processes involving bulk and surface states (SS); (iii) the spin texture of the SS. To do so, NIR and MIR pump-probe experiments will be performed thanks to existing set-ups (low temperature, high magnetic field, fs/ps resolution). To complete these studies, a photocurrent set-up will be developed.