The particle swarm optimization algorithm has predicted a series of binary cadmium hydrides that could be dynamically stable at pressures between 100 GPa and 300 GPa.These low-energy phases are composed of both Cd ato...The particle swarm optimization algorithm has predicted a series of binary cadmium hydrides that could be dynamically stable at pressures between 100 GPa and 300 GPa.These low-energy phases are composed of both Cd atoms and H_(2)molecules.Here,we propose a hitherto unknown metastable Cmcm-CdH_(6)phase,consisting of one-dimensional zigzag graphite-like hydrogenic H_(6)chains,quasimolecular H_(2)units and Cd atoms,which is metallic above 290 GPa.Due to H_(2)s→Cd d donation and Cd d→H_(2)σ^(*)back-donation,the electrons occupy antibonding orbitals for both types of hydrogen atoms.This results in weakened chemical bonds in the Cmcm-CdH_(6)phase via a Kubas-like mechanism,promoting the emergence of high superconductivity,which is estimated to be up to~60 K at 290 GPa.This work will inspire the search for superconductivity in materials based on group IIB hydrides under pressure.展开更多
基金supported by the Jilin Provincial Natural Science Foundation(Grant No.20230101183JC)the Center for Computational Research at Jilin Province.
文摘The particle swarm optimization algorithm has predicted a series of binary cadmium hydrides that could be dynamically stable at pressures between 100 GPa and 300 GPa.These low-energy phases are composed of both Cd atoms and H_(2)molecules.Here,we propose a hitherto unknown metastable Cmcm-CdH_(6)phase,consisting of one-dimensional zigzag graphite-like hydrogenic H_(6)chains,quasimolecular H_(2)units and Cd atoms,which is metallic above 290 GPa.Due to H_(2)s→Cd d donation and Cd d→H_(2)σ^(*)back-donation,the electrons occupy antibonding orbitals for both types of hydrogen atoms.This results in weakened chemical bonds in the Cmcm-CdH_(6)phase via a Kubas-like mechanism,promoting the emergence of high superconductivity,which is estimated to be up to~60 K at 290 GPa.This work will inspire the search for superconductivity in materials based on group IIB hydrides under pressure.
