Since Wigner and Huntington predicted the existence of "metal hydrogen" under high pressure in 1935, "metal hydrogen" has always been a dream target and is called the "holy grail" of high pressure physics. One of the important properties of "metal hydrogen" is its superconductivity. Theoretical calculations show that at 450 GPa (1 GPa = 1 10,000 times atmospheric pressure), "metallic hydrogen" has superconducting properties close to room temperature (TC 242 K). However, such high pressure is a great challenge to the experiment. In 2017, the research group of Harvard University successfully produced 495 GPa of ultra-high pressure force in the laboratory, reporting for the first time the true meaning of "metal hydrogen" (DIAS & SILVERA, Science 2017, 355,715), causing a sensation around the world. Unfortunately, the "metal hydrogen" sample disappeared inexplicably. Therefore, how to obtain "metal hydrogen" under relatively "low" pressure has become an important research direction at present. Recently, Professor Xia Yueyuan, Professor Zhao Mingwen and his collaborators proposed a new method for preparing "metal hydrogen": using the high mechanical strength of carbon nanotubes to form ultra-high density quasi-one-dimensional "metal hydrogen" in carbon nanotubes. Carbon nanotubes can not only protect "metal hydrogen", but also effectively reduce the critical pressure of hydrogen metallization, and realize the metallization and superconductivity of hydrogen at relatively "lower" pressure. Molecular dynamics simulation based on the first principles of quantum mechanics shows that quasi-one-dimensional hydrogen bound to carbon nanotubes can become metal at 163.5 GPa, and its superconducting critical temperature (TC ∼225 K) is also close to room temperature. Based on Eliashberg's superconducting theory, the research team developed a corresponding theoretical model and successfully explained the superconducting characteristics of quasi-one-dimensional "metal hydrogen". This theoretical achievement provides a new scheme for the experimental preparation and research of normal temperature superconductor "metal hydrogen". The research results were published in the journal Nano Letters under the title "hydrogen confirmed in a single wall carbon nanotubes metals and super conductive nanowire under high pressure" (impact factor: 12.712). Professor Xia Yueyuan and Professor Zhao Mingwen of the Institute of Physics are the first author and correspondence author respectively, Professor Ma Yuchen of the Institute of Chemistry and Chemical Engineering is the co-correspondence author, and Shandong University is the only finishing unit. The research work is supported by the National Natural Science Foundation of China, the State Key Laboratory of Crystal Materials and the basic research expenses of Shandong University. In recent years, Zhao Mingwen's team has been devoted to the research of "low dimensional physics". The "topological electronic states, defects and interface effects of low-dimensional systems" completed by this team won the first prize of Shandong Province Natural Science in 2017. In 2017, the team also predicted theoretically the first two-dimensional metal-organic superconducting material Cu-BHT (nano letters 2017, 17, 6166–6170), which was subsequently confirmed by the experimental research institute of academician Zhu Daoben's research group, opening a new field for the research of superconducting materials.
