Speaker: Soo-hyon Phark (Center for Quantum Nanoscience, Institute for Basic Science, Korea)

Time: May 10, 2024 10:00

Place: 理科楼C302

报告摘要：Atom-by-atom addressability, unique in the scanning tunneling microscopy (STM) [1], has enabled control of atomic-scale quantum objects as well as bottom-up design of functional quantum devices. A recent advance in the STM equipped with electron spin resonance (ESR), combining high spatial resolution of STM and high energy resolution of ESR, has enabled magnetic resonance of individual spins on surfaces [2], which raised on-surface single spins as a promising qubit candidate at the atomic scale [3]. In this talk, I first introduce a noble qubit platform using tailored Ti nanostructures on a MgO surface, composed of a sensor and remote spins, where coherent driving and readout of single, two, and three qubits were demonstrated in an all-electrical fashion by means of double electron-electron spin resonance [4–8]. Second, I discuss the spin dynamics of our qubits and present a recent enhancement of the coherence of the Ti atomic spin, achieved by improving the decoupling from the environments inherent in the STM tunnel junction.

References:

1. D. M. Eigler, E. K. Schweizer, Nature 344, 524–526 (1990).

2. S. Baumann et al. Science 350, 417-420 (2015).

3. K. Yang et al. Science 366, 509-512 (2019).

4. Y. Wang et al. npj Quantum Info. 9, 48 (2023).

5. S. Phark et al. Adv. Sci. 10, 2302033 (2023).

6. S. Phark et al. ACS Nano 17, 14144 (2023).

7. Y. Wang et al. Science 382, 87-92 (2023).

8. H. Bui et al. ACS Nano (accepted, 2024).

报告人简介：Soo-hyon is currently working at Center for Quantum Nanoscience (QNS) of Institute for Basic Science. He got his PhD in Solid State Physics from Seoul National University (SNU) in 2006. He had worked as postdocs at SNU and Max-Planck-Institute of Microstructure Physics. His major has been studies on surface nanostructures using a UHV low temperature STM, in particular, spin-polarized STM of spin-resolved electronic structures in magnetic nanostructures. He joined QNS from Oct 2016 and is leading the team “Electron Spin Qubits on Surfaces” using a low-temperature STM equipped with electron spin resonance.