We report a successful tuning of the hole doping level over a wide range in high temperature superconductor Bi2Sr2CaCu2O8＋δ （Bi2212） through successive in situ potassium （K） deposition. By taking high resolution...We report a successful tuning of the hole doping level over a wide range in high temperature superconductor Bi2Sr2CaCu2O8＋δ （Bi2212） through successive in situ potassium （K） deposition. By taking high resolution angleresolved photoemission measurements on the Fermi surface and band structure of an overdoped Bi2212 （To = 76 K） at different stages of K deposition, we found that the area of the hole-like Fermi surface around the Brillouin zone corner （n,n） shrinks with increasing K deposition. This indicates a continuous hole concentration change from initial - 0.26 to eventual 0.09 after extensive K deposition, a net doping level change of 0.17 that makes it possible to bring Bi2212 from being originally overdoped, to optimally-doped, and even- tually becoming heavily underdoped. The electronic behaviors with K deposition are consistent with those of Bi2212 samples with different hole doping levels. These results demonstrate that K deposition is an effective way of in situ controlling the hole concentration in Bi2212. This work opens a good way of studying the doping evolution of electronic structure and establishing the electronic phase diagram in Bi2212 that can be extended to other cuprate superconductors.展开更多
基金XJZ thanks financial support from the National Natural Science foundation of China (11190022,11334010 and 11534007)the National Basic Research Program of China (2015CB921000)the Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB07020300)
文摘We report a successful tuning of the hole doping level over a wide range in high temperature superconductor Bi2Sr2CaCu2O8＋δ （Bi2212） through successive in situ potassium （K） deposition. By taking high resolution angleresolved photoemission measurements on the Fermi surface and band structure of an overdoped Bi2212 （To = 76 K） at different stages of K deposition, we found that the area of the hole-like Fermi surface around the Brillouin zone corner （n,n） shrinks with increasing K deposition. This indicates a continuous hole concentration change from initial - 0.26 to eventual 0.09 after extensive K deposition, a net doping level change of 0.17 that makes it possible to bring Bi2212 from being originally overdoped, to optimally-doped, and even- tually becoming heavily underdoped. The electronic behaviors with K deposition are consistent with those of Bi2212 samples with different hole doping levels. These results demonstrate that K deposition is an effective way of in situ controlling the hole concentration in Bi2212. This work opens a good way of studying the doping evolution of electronic structure and establishing the electronic phase diagram in Bi2212 that can be extended to other cuprate superconductors.
