报告题目：Atomic-scale magnetic resonance of quantum spins on a surface
报告人：杨锴 教授 中科院物理所
Recently, the ability to drive electron spin resonance (ESR) of individual atoms using a scanning tunneling microscope (STM) provided a major step forward in sensing and manipulating magnetism at the atomic scale. In the first part, I will describe the implementation of continuous-wave ESR in STM. The ultrahigh energy resolution of ESR has allowed the measurement of the magnetic interaction between two atoms, the detection of nuclear spins, as well as the exploration of quantum fluctuations in designed spin arrays. Next, I will talk about coherent spin control using all-electric pulsed ESR. By modulating the atomically-confined magnetic interaction between the STM tip and surface atoms, we drive quantum Rabi oscillations of single spins in as little as ~20 nanoseconds. Ramsey fringes and spin echo signals allow us to improve quantum coherence. I will also show the coherent operations on engineered atomic dimers. Coherent control of spins arranged with atomic precision thus provides a solid-state platform for quantum simulation of many-body systems.
 S. Baumann et al., Science 350, 417 (2015).
 K. Yang et al., Nat. Nanotechnol. 13, 1120 (2018).
 K. Yang, et al., Science 366, 509 (2019).
Kai Yang is an associate professor at the Institute of Physics, Chinese Academy of Sciences. Before joining IOP-CAS, he worked at the IBM Almaden Research Center as a postdoctoral researcher. His research focuses on characterizing and manipulating quantum materials at the atomic scale, using a versatile quantum sensing tool combining two imaging methods: electron spin resonance (ESR) and scanning tunneling microscopy (STM). The ESR-STM provides a unique access to the quantum materials with energy resolution beyond the thermal limit and with atomic-scale spatial resolution. The ultimate goal is to harness these quantum properties for quantum sensing and quantum information processing.