Using Hyperoptimized Tensor Networks and First-Principles Electronic Structure to Simulate the Experimental Properties of the Giant {Mn 84 } Torus
Using Hyperoptimized Tensor Networks and First-Principles Electronic Structure to Simulate the Experimental Properties of the Giant {Mn 84 } Torus
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使用超优化张量网络和第一原理电子结构模拟巨型{Mn 84 }环面的实验特性
DOI：
10.1021/acs.jpclett.2c00354
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Cheng, Hai-Ping
中科院分区：
文献类型：
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作者：
Chen, Dian-Teng;Helms, Phillip;Hale, Ashlyn R.;Lee, Minseong;Li, Chenghan;Gray, Johnnie;Christou, George;Zapf, Vivien S.;Chan, Garnet Kin-Lic;Cheng, Hai-Ping
单分子磁体{Mn 84}由于其高的成核性而对理论提出了挑战。我们直接计算两个实验上可观察到的，磁场相关的磁化强度高达75 T和温度相关的热容，使用无参数理论。特别是，我们使用第一性原理计算，以获得短期和长期的交换相互作用，并计算所产生的经典Potts和伊辛自旋模型的精确配分函数为所有84 MnS= 2自旋，以获得可观的。后者的计算是通过使用超优化张量网络收缩来实现的，这是一种为模拟量子霸权电路而开发的技术。我们还合成了磁体，并测量其热容和磁化强度，观察理论和实验之间的定性一致性，并确定了热容中的异常凸起和磁化强度中的平台。我们的工作还确定了目前的理论模型在大型磁体，如小，远程交换耦合的灵敏度的一些限制。
The single-molecule magnet {Mn84} is a challenge to theory because of its high nuclearity. We directly compute two experimentally accessible observables, the field-dependent magnetization up to 75 T and the temperature-dependent heat capacity, using parameter-free theory. In particular, we use first-principles calculations to derive short- and long-range exchange interactions and compute the exact partition function of the resulting classical Potts and Ising spin models for all 84 MnS= 2 spins to obtain observables. The latter computation is made possible by using hyperoptimized tensor network contractions, a technique developed to simulate quantum supremacy circuits. We also synthesize the magnet and measure its heat capacity and magnetization, observing qualitative agreement between theory and experiment and identifying an unusual bump in the heat capacity and a plateau in the magnetization. Our work also identifies some limitations of current theoretical modeling in large magnets, such as sensitivity to small, long-range exchange couplings.