Optically and Electrically Controllable Adatom Spin-orbital Dynamics in Transition Metal Dichalcogenides.

Shao, Bin; Schüler, Malte; Schönhoff, Gunnar; Frauenheim, Thomas; Czycholl, Gerd; Wehling, Tim O · Nano Lett · 2017

basic_science · Level V

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Abstract

We analyze the interplay of spin-valley coupling, orbital physics, and magnetic anisotropy taking place at single magnetic atoms adsorbed on semiconducting transition metal dichalcogenides, MX<sub>2</sub> (M = Mo, W; X = S, Se). Orbital selection rules turn out to govern the kinetic exchange coupling between the adatom and charge carriers in the MX<sub>2</sub> and lead to highly orbitally dependent spin-flip scattering rates, as we illustrate for the example of transition metal adatoms with d<sup>9</sup> configuration. Our ab initio calculations suggest that d<sup>9</sup> configurations are realizable by single Co, Rh, or Ir adatoms on MoS<sub>2</sub>, which additionally exhibit a sizable magnetic anisotropy. We find that the interaction of the adatom with carriers in the MX<sub>2</sub> allows to tune its behavior from a quantum regime with full Kondo screening to a regime of "Ising spintronics" where its spin-orbital moment acts as classical bit, which can be erased and written electronically and optically.