报告人：黄万通 博士（卡尔斯鲁厄理工学院）

报告题目：Spin Engineering in Artificial Atom-Molecule Hybrids

报告时间：2024年4月12日上午10:00

报告地点：909-B厅

报告摘要：

Control of single electron spins constitutes one of the most promising platforms for spintronics, quantum sensing, and quantum information processing. Realizing prolonged relaxation (T1) and coherence (T2) times is a major challenge of current quantum technology, such as ion traps, quantum dots, color centers. For spins on surfaces, electron spin resonance – scanning tunneling microscopy (ESR-STM) has provided excellent access to coherent manipulation, however, T1 and T2 times remain short (about 100-300 ns). Here, we fabricate qubits with both T1 and T2 exceeding 1 µs in artificially engineered hybrids of atomic and molecular spins. The resulting magnetic system consisting of an iron phthalocyanine (FePc) molecule coupled to a Fe atom, forms a mixed spin (1/2,1) quantum Ferrimagnet. We show that the strong exchange coupling leads to a ground-state doublet, which is partially entangled and thus constitutes the smallest possible “spin cluster” qubit. Thus, this hybrid behaves like an effective spin ½ system, acting as a tunable qubit system. Our calculations show that the longer T1 can be derived from a suppression of inelastic scattering channels as a consequence of the correlation. Moreover, we show that the effective spin ½ system can be coupled to others and scaled up, allowing to realize larger structures. Moreover, we show by building trimers and dimers of hybrids that their spins can be coupled providing a path to realizing larger structures. We believe, that such magnetic prototype structures provide a versatile platform to study complex magnetic interactions and potentially improve spin dynamics on the atomic scale.

个人简介 ：

黄万通，2014年毕业于南开大学物理学院，获物理学学士学位。2020年毕业于清华大学，获物理学博士学位。2021年－至今，在德国卡尔斯鲁厄理工学院物理系从事博士后研究。博士期间利用稀释制冷扫描隧道显微镜研究TaS₂，NbSe₂，FeSe等二维材料在极低温强磁场条件下的物性；博后期间参与搭建干式稀释制冷-电子自旋共振-扫描隧道显微镜（ESR-STM），用其研究单个原子，分子及其杂化物的磁性并构造量子比特，旨在提高单量子比特的自旋寿命和相干时间。

联系人：仲启刚 教授