Efficient driving of a spin-qubit using single-atom magnets

The realization of electron spin resonance in a scanning tunneling microscopy (ESR-STM) has opened a new avenue for the coherent quantum sensing and quantum state manipulation [1]. Utilizing ESR-STM, a novel qubit platform has recently emerged, where each qubit is formed by an electron spin coupled to a nearby single-atom magnet which allows to drive the spin in the absence of a tunneling current. This raises questions about the driving mechanism originating from the single-atom magnet [2]. In this work, we propose that a modulation of the exchange coupling between the single atom magnet and the spin qubit is responsible for driving the electron spin [3]. Our simulations show Rabi rates in agreement with reliable experimental data [4]. We demonstrate how single-atom magnets can be used to drive a nearby quantum spin qubit efficiently and discuss the optimization for Rabi rates by adjusting experimental parameters.

[1] S. Baumann, W. Paul, T. Choi, C. P. Lutz, A. Ardavan, and A. J. Heinrich, Electron paramagnetic resonance of individual atoms on a surface, Science 350, 417 (2015).

[2] Y. Wang, Y. Chen, H. T. Bui, C. Wolf, M. Haze, C. Mier, J. Kim, D. J. Choi, C. P. Lutz, Y. Bae, S. H. Phark, and A. J. Heinrich, An atomic-scale multi-qubit platform, Science 382, 87 (2023).

[3] J. Reina-Galvez, H.-A. Le, H. T. Bui, S.-h. Phark, N. Lorente, and C. Wolf, Efficient driving of a spin-qubit using single-atom magnets, arXiv:2408.07289 (2024).

[4] S. h. Phark, H. T. Bui, A. Ferron, J. Fernandez-Rossier, J. Reina-Galvez, C. Wolf, Y. Wang, K. Yang, A. J. Heinrich, and C. P. Lutz, Electric-Field-Driven Spin Resonance by On-Surface Exchange Coupling to a Single-Atom Magnet, Advanced Science 10, 1 (2023).