Quantum Spin‐1/2 Rings Built From [2]Triangulene Molecular Units
Abstract
ABSTRACT Quantum spin rings represent fundamental model systems that exhibit distinctive quantum phenomena arising from their periodic boundary conditions and enhanced quantum fluctuations. Here, we report the on‐surface synthesis and atomic‐scale characterization of antiferromagnetic S = 1/2 quantum spin rings composed of pristine [2]triangulene units on Au(111). Using stepwise on‐surface synthesis followed by scanning tunneling microscopy tip‐induced dehydrogenation, we precisely constructed cyclic five‐ and six‐membered spin rings and investigated their spin states via scanning probe microscopy and multireference calculations. Bond‐resolved noncontact atomic force microscopy imaging reveals that the six‐membered ring retains a planar geometry, whereas the five‐membered ring exhibits pronounced structural distortion. The six‐membered ring hosts a uniform excitation gap that can be accurately described by a Heisenberg spin model and multireference CASCI calculations. In contrast, although an ideal C 5 ‐symmetric pentamer is theoretically expected to host a degenerate, frustrated ground state, the experimentally realized five‐membered ring is structurally distorted, which lifts this degeneracy and produces asymmetric spatial distributions of the spin ground state. Our findings establish a versatile molecular platform for exploring correlated magnetism and quantum spin phenomena in cyclic organic magnetic architectures.
Article Details
Authors (17)
Can Li
State Key Laboratory of Catalysis
Manish Kumar
Ying Wang
Diego Manuel Soler Polo
Institute of Physics Czech Academy of Sciences Prague Czech Republic
Yi‐Jun Wang
State Key Laboratory of Natural Medicines School of Pharmacy China Pharmaceutical University Nanjing China
He Qi
Liang Liu
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Tsung-Dao Lee Institute, School of Physics and Astronomy
Xiaoxue Liu
Dandan Guan
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Tsung-Dao Lee Institute, School of Physics and Astronomy
Yaoyi Li
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Tsung-Dao Lee Institute, School of Physics and Astronomy
Hao Zheng
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
Canhua Liu
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Tsung-Dao Lee Institute, School of Physics and Astronomy
Jinfeng Jia
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Tsung-Dao Lee Institute, School of Physics and Astronomy
Pei‐Nian Liu
State Key Laboratory of Natural Medicines School of Pharmacy China Pharmaceutical University Nanjing China
Pavel Jelínek
Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.
Deng‐Yuan Li
State Key Laboratory of Natural Medicines School of Pharmacy China Pharmaceutical University Nanjing China
Shiyong Wang
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy