Exploring superconductivity in dynamically stable carbon-boron clathrates trapping molecular hydrogen  

作　　者：Akinwumi Akinpelu Mangladeep Bhullar Timothy A.Strobel Yansun Yao 

机构地区：[1]Department of Physics and Engineering Physics,University of Saskatchewan,Saskatoon,Saskatchewan,S7N 5E2,Canada [2]Earth and Planets Laboratory,Carnegie Institution for Science,5241 Broad Branch Road,Northwest,Washington DC 20015,USA

出　　处：《Chinese Physics B》2025年第3期131-140,共10页中国物理B(英文版)

基　　金：supported by Carnegie Canada and Natural Sciences and Engineering Research Council of Canada(NSERC);support from the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences,under Award No.DESC0020683。

摘　　要：The recent discovery of type-Ⅶboron-carbon clathrates with calculated superconducting transition temperatures approaching~100 K has sparked interest in exploring new conventional superconductors that may be stabilized at ambient pressure.The electronic structure of the clathrate is highly tunable based on the ability to substitute different metal atoms within the cages,which may also be large enough to host small molecules.Here we introduce molecular hydrogen(H_(2))within the clathrate cages and investigate its impact on electron-phonon coupling interactions and the superconducting transition temperature(T_(c)).Our approach involves combining molecular hydrogen with the new diamond-like covalent framework,resulting in a hydrogen-encapsulated clathrate,(H_(2))B_(3)C_(3).A notable characteristic of(H_(2))B_(3)C_(3)is the dynamic behavior of the H_(2)molecules,which exhibit nearly free rotations within the B-C cages,resulting in a dynamic structure that remains cubic on average.The static structure of(H_(2))B_(3)C_(3)(a snapshot in its dynamic trajectory)is calculated to be dynamically stable at ambient and low pressures.Topological analysis of the electron density reveals weak van der Waals interactions between molecular hydrogen and the B-C cages,marginally influencing the electronic structure of the material.The electron count and electronic structure calculations indicate that(H_(2))B_(3)C_(3)is a hole conductor,in which H_(2)molecules donate a portion of their valence electron density to the metallic cage framework.Electron-phonon coupling calculation using the Migdal-Eliashberg theory predicts that(H_(2))B_(3)C_(3)possesses a T_(c) of 46 K under ambient pressure.These results indicate potential for additional light-element substitutions within the type-Ⅶclathrate framework and suggest the possibility of molecular hydrogen as a new approach to optimizing the electronic structures of this new class of superconducting materials.

关 键 词：SUPERCONDUCTIVITY electronic structure density functional theory molecular dynamics 

分 类 号：TG1[金属学及工艺—金属学]