Coherent ultrafast spin-dynamics probed in three dimensional topological insulators

TL;DR

This paper demonstrates coherent femtosecond control of spin-polarization in topological insulators, revealing new possibilities for ultrafast spintronic applications by manipulating spin states with light.

Contribution

It introduces a method to coherently control spin-polarization in topological insulators using ultrafast laser pulses, advancing spintronic technology.

Findings

Successful femtosecond control of spin-polarization

Observation of spin dynamics near the Dirac cone

Potential for ultrafast spintronic devices

Abstract

Topological insulators are candidates to open up a novel route in spin based electronics. Different to traditional ferromagnetic materials, where the carrier spin-polarization and magnetization are based on the exchange interaction, the spin properties in topological insulators are based on the coupling of spin- and orbit interaction connected to its momentum. Specific ways to control the spin-polarization with light have been demonstrated: the energy momentum landscape of the Dirac cone provides spin-momentum locking of the charge current and its spin. The directionality of spin and momentum, as well as control with light has been demonstrated. Here we demonstrate a coherent femtosecond control of spin-polarization for states in the valence band at around the Dirac cone.