We have studied the doping-driven orbital-selective Mott transition in multi-band Hubbard models with equal band width in the presence of crystal field splitting. Crystal field splitting lifts one of the bands while l...We have studied the doping-driven orbital-selective Mott transition in multi-band Hubbard models with equal band width in the presence of crystal field splitting. Crystal field splitting lifts one of the bands while leaving the others degener- ate. We use single-site dynamical mean-field theory combined with continuous time quantum Monte Carlo impurity solver to calculate a phase diagram as a function of total electron filling N and crystal field splitting A. We find a large region of orbital-selective Mott phase in the phase diagram when the doping is large enough. Further analysis indicates that the large region of orbital-selective Mott phase is driven and stabilized by doping. Such models may account for the orbital-selective Mott transition in some doped realistic strongly correlated materials.展开更多
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Project supported by the National Natural Science Foundation of China(Grant No.2011CBA00108)the National Basic Research Program of China(Grant No.2013CB921700)
文摘We have studied the doping-driven orbital-selective Mott transition in multi-band Hubbard models with equal band width in the presence of crystal field splitting. Crystal field splitting lifts one of the bands while leaving the others degener- ate. We use single-site dynamical mean-field theory combined with continuous time quantum Monte Carlo impurity solver to calculate a phase diagram as a function of total electron filling N and crystal field splitting A. We find a large region of orbital-selective Mott phase in the phase diagram when the doping is large enough. Further analysis indicates that the large region of orbital-selective Mott phase is driven and stabilized by doping. Such models may account for the orbital-selective Mott transition in some doped realistic strongly correlated materials.
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.
