December 2, 2023, ADV funct. mater.**Published research by Professor Shi Junjie of Peking University, Zhu Yao-hui of Beijing Technology and Business University and Du Juan of Beijing University of Technology**, entitled "few-hydrogen metal-bonded perovskite superconductor mghcu3 with a critical temperature of 42 K under atmospheric". pressure》。
Since Ashcroft's 2004 introduction of polyhydrogen high-temperature superconductors, a number of possible candidate materials have been proposed, for example, LAH10 has shown the highest superconducting transition temperature (TC) to date at around 250-260 K at 170-200 GPA. However, this pressure is too great to be practically used. In this study, the authors proposed the concept of metal-bonded perovskites and investigated the structural stability, electron-phonon interaction, and superconductivity properties of MGHCU3 by combining first-principles calculations, Wannier interpolation, and solving the ME equation.
The main conclusions are summarized as follows: (1) As an environmentally friendly and low-cost compound, perovskite mGHCU3 bonded with less hydrogen metal is easier to synthesize than polyhydrohydride. (2) The metallic bonds in this system provide excellent structural stability under ambient stress and produce better ductility than polyhydrogen, copper, and iron-based superconductors bound by covalent and ionic bonds. (3) It was found that the introduction of hydrogen increased the TC of MGHCU3 to 42 K by affecting the electronic and phononic structures as well as the EPC constant. (4) By adding a hydrogen atom to the FCC-like MgCu3, the EPC constant increases to 083 (MGHCU3), which is greater than the EPC constant of MGB2, and it converts the non-superconductor MGCu3 into the superconductor MGHCU3. (5) The anisotropic effects found in this system are due to the ternary structure, the influence of hydrogen, and the anisotropic EPC interaction, which increases the isotropic TC by 42%. (6) The TC42 K obtained by the phonon-mediated superconductor MGHCU3 is superior to that of the most commonly used MGB2 and NB3GE. The first-class ternary metal-bonded perovskite MGHCU3 enriches the perovskite family and will facilitate further research on low-hydrogen superconductors at atmospheric pressure.
Fig.1 Schematic diagram of the structure and properties of less hydrogen metal bonded perovskite AHB3 and polyhydrohydride MH6.
Fig.2. Structure and stability of metal-bonded perovskite MGHCU3.
Fig.3 Comparison of electronic structure and density of states between mghCu3 and mgh0cu3.
Fig. 4 Phonon spectrum, electron-phonon coupling (EPC), and Fermi surface (FS) nesting functions.
Fig.5 EPC strength and superconducting energy gap of mGHcu3.
Fig.6 Relationship between specific heat difference and temperature between the superconducting state and the normal state of MGHCU3.
tian, c., he, y., zhu, y. et al. few-hydrogen metal-bonded perovskite superconductor mghcu3 with a critical temperature of 42 k under atmospheric pressure. adv. funct. mater., 2023, 2304919.
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