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Tuning Single-Atom Electron Spin Resonance in a Vector Magnetic Field.
Philip Willke1,2, Aparajita Singha1,2, Xue Zhang1,2
1Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea.
Nano Letters
|October 30, 2019
Summary
Optimizing magnetic fields significantly enhances single-atom electron spin resonance (ESR) signal amplitude. This technique, using scanning tunneling microscopy (STM), can now be performed with only the tip
Area of Science:
- Surface Science and Quantum Technologies
- Atomic-scale Magnetic Resonance Spectroscopy
Background:
- Single spin centers are crucial for quantum sensing and coherent manipulation.
- Electron spin resonance (ESR) combined with scanning tunneling microscopy (STM) offers high-resolution magnetic property detection at the atomic scale.
- The precise role of magnetic fields in these experiments has remained largely unexamined.
Purpose of the Study:
- To elucidate the role of magnetic fields in single-atom ESR experiments.
- To optimize magnetic field configurations for enhanced ESR signal amplitude.
- To explore the utility of the magnetic STM tip's stray field for ESR measurements.
Main Methods:
- Single-atom ESR measurements on individual Fe atoms on MgO.
- Utilized a two-dimensional vector magnetic field and the local field of a magnetic STM tip.
- Employed tip-field sweeps for constant-frequency ESR measurements.
Main Results:
- Optimized magnetic fields greatly improved ESR amplitude, with notable enhancement at large in-plane fields.
- The magnetic STM tip's stray field efficiently drives electron spins.
- Demonstrated successful ESR measurements using solely the tip field, even at zero external magnetic field.
Conclusions:
- Magnetic field optimization is key to improving single-atom ESR sensitivity.
- The magnetic STM tip is a versatile tool for driving spins and enabling ESR measurements.
- Performing ESR solely with the tip field significantly broadens the accessibility of this technique in existing STM systems.
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