Investigation of Single Atom Magnets using Scanning Tunneling Microscopy enabled Electron Spin Resonance

The smallest classical storage unit is a single atom bit. Its recent discovery in form of magnetically bistable holmium single atom magnets on MgO exemplified how miniaturization could be realized down to fundamental limits1 . Here we discuss the experiments leading to the observation of magnetic remanence1 , the reading and writing of single atom magnets 2 , and the investigation of their thermal and magnetic stability3 . Using STM enabled electron spin resonance4,5 , we find a magnetic moment of (10.1±0.1) Bohr magnetons and we prove the magnetic origin of the tunneling bias voltage dependent 2-state switching observed with spin-polarized current. We briefly review the used measurement concept of ESR-STM and illustrate new avenues for this technique.

1. Donati, F. et al. Magnetic remanence in single atoms. Science 352, 318–321 (2016).

2. Natterer, F. D. et al. Reading and writing single-atom magnets. Nature 543, 226–228 (2017).

3. Natterer, F. D., Donati, F., Patthey, F. & Brune, H. Thermal and Magnetic-Field Stability of

Holmium Single-Atom Magnets. Phys. Rev. Lett. 121, 027201 (2018).

4. Baumann, S. et al. Electron paramagnetic resonance of individual atoms on a surface. Science 350,417–420 (2015).

5. Natterer, F. D. et al. Upgrade of a low-temperature scanning tunneling microscope for electron- spin resonance. ArXiv181003887 Cond-Mat Physics (2018).