文献类型：期刊文献

英文题名：Quantum phase transition in magnetic nanographenes on a lead superconductor

作者：Liu, Yu[1]; Li, Can[1]; Xue, Fu-Hua[2]; Wang, Ying[2]; Huang, Haili[3]; Yang, Hao[3]; Chen, Jiayi[1]; Guan, Dan-Dan[1,3]; Li, Yao-Yi[1,3]; Zheng, Hao[1,3]; Liu, Canhua[1,3]; Qin, Mingpu[1,3]; Wang, Xiaoqun[1,3]; Li, Deng-Yuan[2]; Liu, Pei-Nian[2]; Wang, Shiyong[1,3]; Jia, Jinfeng[1,3]

机构：[1] Key Laboratory of Artificial Structures and Quantum Control [Ministry of Education], Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China; [2] Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, State Key Laboratory of Chemical Engineering, School of Chemistry and Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, 200237, China; [3] Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China

年份：2022

外文期刊名：arXiv

收录：EI(收录号：20220293918)

语种：英文

外文关键词：Crystal symmetry - Ground state - Honeycomb structures - Magnetic anisotropy - Magnetism - Phase transitions - Quantum theory - Scanning tunneling microscopy - Superconducting materials

摘要：Quantum spins, referred to the spin operator preserved by full SU(2) symmetry in the absence of the magnetic anistropy1-3, have been proposed to host exotic interactions with superconductivity4. However, spin orbit coupling5,6 and crystal field splitting7,8 normally cause a significant magnetic anisotropy for d/f-shell spins on surfaces6,9, breaking SU(2) symmetry and fabricating the spins with Ising properties10. Recently, magnetic nanographenes have been proven to host intrinsic quantum magnetism due to their negligible spin orbital coupling and crystal field splitting10-12. Here, we fabricate three atomically precise nanographenes with the same magnetic ground state of spin S=1/2 on Pb(111) through engineering sublattice imbalance in graphene honeycomb lattice13. Scanning tunneling spectroscopy reveals the coexistence of magnetic bound states and Kondo screening in such hybridized system14. Through engineering the magnetic exchange strength between the unpaired spin in nanographenes and cooper pairs, quantum phase transition from the singlet to the doublet state has been observed, in consistent with quantum models of spins on superconductors1,14,15. Our work demonstrates delocalized graphene magnetism host highly tunable magnetic bound states with cooper pairs, which can be further developed to study the Majorana bound states16-19 and other rich quantum physics of low-dimensional quantum spins on superconductors10,12 ? 2022, CC BY.