Abstract
We report on the quenching of single Ni adatom moments on Te-terminated and topological insulator surfaces. The effect is noted as a missing x-ray magnetic circular dichroism for resonant transitions into partially filled Ni states of theory-derived occupancy . On the basis of a comparative study of Ni and Fe using scanning tunneling microscopy and ab initio calculations, we are able to relate the element specific moment formation to a local Stoner criterion. Our theory shows that while Fe adatoms form large spin moments of with out-of-plane anisotropy due to a sufficiently large density of states at the Fermi energy, Ni remains well below an effective Stoner threshold for local moment formation. With the Fermi level remaining in the bulk band gap after adatom deposition, nonmagnetic Ni and preferentially out-of-plane oriented magnetic Fe with similar structural properties on surfaces constitute a perfect platform to study the off-on effects of time-reversal symmetry breaking on topological surface states.
- Received 7 April 2016
- Revised 13 July 2016
DOI:https://doi.org/10.1103/PhysRevB.94.161114
©2016 American Physical Society