On February 28, Nature Communications published an article titled “Kosterlitz-Thouless Melting of Magnetic Order in the Triangular Quantum Ising Material TmMgGaO4”, a joint effort by the Beihang research team at the key Laboratory of Micro-Nano Measurement-Manipulation and Physics including Dr. Li Wei, his doctoral student Li Han and others, as well as collaborators from Fudan University, the Institute of Physics of the Chinese Academy of Sciences and the University of Hong Kong.
The research reported the latest achievements in the quantum theory of triangular-lattice antiferromagnet. In the article, a protocol of employing many-body computation methodologies for accurate model calculations — of both equilibrium and dynamical properties — for a frustrated rare-earth magnet TmMgGaO4 (TMGO) was implemented. It was also shown that a strange two-dimensional Kosterlitz-Thouless (KT) phase floated at intermediate temperatures. Previously, the KT phase transition has been observed in two-dimensional superfluids and superconductors, and this theoretical work for the first time predicted the material realization of the KT transition in 2D magnets.
Since 2015, the research group of Dr. Li Wei has long focused on the quantum many-body physics and tensor network approach, and applied it to the study of correlated matter and quantum materials with novel emerging properties. In addition, the researchers proposed the tensor renormalization group approach and made high-level original achievements, which were published in Physical Review X and Physical Review Letters.
By using the tensor renormalization group approach, Li Han, the first author supervised by Dr. Li Wei, conducted large-scale calculations and accurately determined the model parameters of TMGO model according to the experimental measurements. The other first author is Liao Yuanda, a doctoral student from the Institute of Physics of the Chinese Academy of Sciences, adopted the Monte Carlo method to carry out large-scale calculations. Professor Qi Yang from Fudan University, Associate Professor Meng Ziyang from the University of Hong Kong and Associate Professor Li Wei from Beihang University, as corresponding authors, conducted research on quantum field theory, self spectroscopy and thermodynamic properties. The three co-authors are Chen Binbin (a doctoral student supervised by Prof. Chen Ziyu), who assist in the work on tensor and Monte Carlo calculations, Assistant Professor Sheng Xianlei and his postgraduate student Zeng Xutao who carried out calculations and analysis of TMGO with the density functional method.
The work was supported by the National Natural Science Foundation of China, Beihang Excellence Cultivation Program, Beihang Youth Talent Fund, etc.
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Reported by Liu Rui
Reviewed by Li Guanghao
Edited by Jia Aiping
Translated by Feng Yueyue