报告人简介：

   Shichao Yan is now an assistant professor (Principle Investigator) in ShanghaiTech University. He received his Ph.D. in condensed matter physics from the Institute of Physics, Chinese Academy of Sciences in 2012. During his Ph.D., he visited Prof. Wilson Ho’s group at University of California, Irvine in 2008. After graduation, he joined Max Planck Institute and University of Illinois at Urbana-Champaign from 2012 to 2017 as a postdoctoral researcher. Shichao Yan's current research interest is in studying quantum materials and atomic-scale nanomagnets by using low-temperature scanning tunneling microscopy and spectroscopy. So far, he has published papers as first author or corresponding author in journals including Nature Nanotechnology, Science Advances, Physical Review Letters, Nano Letters etc.

报告摘要：

      Quantum nanomagnets have attracted great research interests as their potential applications in spintronics and quantum computations. Here we use scanning tunneling microscope (STM) atom manipulation technique to construct nanomagnets atom-by-atom. We study the novel functionalities and magnetic properties of these artificially constructed nanomagnets with spin-resolved and time-resolved STM.

In this talk, I will present three examples about the quantum nanomagnets on surfaces. First, we find that when a three-atom nanomagnet (Fe trimer) is placed in the tunnel junction of spin-polarized STM, it will show strong negative differential resistance (NDR). This NDR occurs due to the occupation of the long-lived spin state of Fe trimer which reduces the tunneling rates of the spin-polarized tunneling electrons. This mechanism is spin-based and differs from the previously known NDR mechanism. Second, I will demonstrate that the spin dynamics of Fe trimer is extremely sensitive to its local magnetic environment and it can be used as a spin sensor to nonlocally detect the magnetic states of nearby nano-antiferromagnets. In the last part, I will talk about engineering many-body quantum state, Kondo state, in an atomic spin chain.