The discovery of Ni-based superconductors has brought new hope to the field of high-temperature superconductivity.Understanding the dimensional characteristics and anisotropy of nickelate superconductors has become a ...The discovery of Ni-based superconductors has brought new hope to the field of high-temperature superconductivity.Understanding the dimensional characteristics and anisotropy of nickelate superconductors has become a central focus in current research.However,the nature of the nickelate superconductivity,especially the transition between 2D and 3D superconductivity,remains debated.In this study,we investigated the magnetic field-dependent electrical transport behaviors of infinite-layer nickelates.The La_(0.8)Sr_(0.2)NiO_(2)films exhibit highly anisotropic superconductivity,which fits well with the 2D Tinkham model,indicating a purely 2D superconducting nature.In contrast,the Nd_(0.8)Sr_(0.2)NiO_(2)films show isotropic behavior with a mixed 2D+3D superconducting characteristics.This“mixed 2D+3D superconducting behavior”is typically associated with the complexity of the electronic band structure in the material.Through a systematic comparison of two model systems with distinct rare-earth orbital contributions,we propose a new perspective based on orbital selectivity.The observed difference likely originates from Nd_(0.8)Sr_(0.2)NiO_(2)incorporates the Nd_(0.8)Sr_(0.2)NiO_(2)orbital,adding a 3D component.Its interaction with the Ni sd_(2)2orbital leads to orbital-selective pairing.Theoretical calculations provide key evidence that the Nd-based system exhibits greater isotropy and 3D character compared to the La-based system.Our study thus suggests that orbital selectivity serves as a critical mechanism governing the superconducting properties,and the distinction between rare-earth elements(such as La and Nd)ultimately influences the dimensional characteristics of superconductivity through this mechanism.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52525208)the Sichuan Science and Technology Program(Grant No.2024ZYD0164)+2 种基金the Key Research and Development Program from the Ministry of Science and Technology(Grant No.2023YFA1406301)the National Natural Science Foundation of China(Grant Nos.12274061,and 12204090)the Technology Department of Sichuan Province(Grant No.2023NSFSC1336)。
文摘The discovery of Ni-based superconductors has brought new hope to the field of high-temperature superconductivity.Understanding the dimensional characteristics and anisotropy of nickelate superconductors has become a central focus in current research.However,the nature of the nickelate superconductivity,especially the transition between 2D and 3D superconductivity,remains debated.In this study,we investigated the magnetic field-dependent electrical transport behaviors of infinite-layer nickelates.The La_(0.8)Sr_(0.2)NiO_(2)films exhibit highly anisotropic superconductivity,which fits well with the 2D Tinkham model,indicating a purely 2D superconducting nature.In contrast,the Nd_(0.8)Sr_(0.2)NiO_(2)films show isotropic behavior with a mixed 2D+3D superconducting characteristics.This“mixed 2D+3D superconducting behavior”is typically associated with the complexity of the electronic band structure in the material.Through a systematic comparison of two model systems with distinct rare-earth orbital contributions,we propose a new perspective based on orbital selectivity.The observed difference likely originates from Nd_(0.8)Sr_(0.2)NiO_(2)incorporates the Nd_(0.8)Sr_(0.2)NiO_(2)orbital,adding a 3D component.Its interaction with the Ni sd_(2)2orbital leads to orbital-selective pairing.Theoretical calculations provide key evidence that the Nd-based system exhibits greater isotropy and 3D character compared to the La-based system.Our study thus suggests that orbital selectivity serves as a critical mechanism governing the superconducting properties,and the distinction between rare-earth elements(such as La and Nd)ultimately influences the dimensional characteristics of superconductivity through this mechanism.
