Engineering atomic-scale magnetic fields by dysprosium single atom magnets

JULY 7, 2021

Aparajita Singha, Philip Willke, T. Bilgeri, Xue Zhang, H. Brune, Fabio Donati, Andreas Heinrich & Taeyoung Choi
Nature Communications 12, 4179 (2021)


Designing magnetic fields at the ultimate limit of single atoms is an interesting physics problem. Researchers from QNS has made this possible by using ultra-stable dysprosium single atom magnets on insulating magnesium oxide surface.


Atomic scale engineering of magnetic fields is a key ingredient for miniaturizing quantum devices and precision control of quantum systems. This requires a unique combination of magnetic stability and spin-manipulation capabilities. Surface-supported single atom magnets offer such possibilities, where long temporal and thermal stability of the magnetic states can be achieved by maximizing the magnet/ic anisotropy energy (MAE) and by minimizing quantum tunnelling of the magnetization. Here, we show that dysprosium (Dy) atoms on magnesium oxide (MgO) have a giant MAE of 250 meV, currently the highest among all surface spins. Using a variety of scanning tunnelling microscopy (STM) techniques including single atom electron spin resonance (ESR), we confirm no spontaneous spin-switching in Dy over days at ≈ 1 K under low and even vanishing magnetic field. We utilize these robust Dy single atom magnets to engineer magnetic nanostructures, demonstrating unique control of magnetic fields with atomic scale tunability.