Stilp Fabian, Bereczuk Andreas, Berwanger Julian, Mundigl Nadine, Richter Klaus, Giessibl Franz J
Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93040 Regensburg, Germany.
Institute of Theoretical Physics, Department of Physics, University of Regensburg, 93040 Regensburg, Germany.
Science. 2021 Jun 11;372(6547):1196-1200. doi: 10.1126/science.abe2600. Epub 2021 May 13.
We explored the bonding properties of the quantum corral (a circle of 48 iron atoms placed on a copper surface) reported by Crommie in 1993, along with variants, as an artificial atom using an atomic force microscope (AFM). The original corral geometry confines 102 electrons to 28 discrete energy states, and we found that these states can form a bond to the front atom of the AFM with an energy of about 5 millielectron volts. The measured forces are about 1/1000 of typical forces in atomically resolved AFM. The confined electrons showed covalent attraction to metal tips and Pauli repulsion to CO-terminated tips. The repulsion at close distance was evident from the response of corral states created by deliberately placing single iron atoms inside the corral. The forces scaled appropriately with a 24-atom corral.
我们利用原子力显微镜（AFM）研究了1993年由克罗米报告的量子围栏（放置在铜表面的一圈48个铁原子）及其变体的键合特性，将其作为一种人造原子。原始的围栏几何结构将102个电子限制在28个离散的能量状态，我们发现这些状态可以与AFM的前端原子形成能量约为5毫电子伏特的键。测量到的力约为原子分辨AFM中典型力的1/1000。被限制的电子对金属尖端表现出共价吸引力，对CO终止的尖端表现出泡利排斥力。通过故意在围栏内放置单个铁原子所产生的围栏状态的响应，可以明显看出近距离的排斥力。对于一个24原子的围栏，力的比例关系是合适的。
