By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the d...By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.展开更多
We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, w...We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, we identify the existence of the Fermi arcs originated from topological surface states. Furthermore, the surface states exhibit circular dichroism pattern, which may correlate with its non-trivial spin texture. Our results provide critical evidence for the existence of the Weyl Fermions in NbP, which lays the foundation for further research.展开更多
基金Supported by the National Basic Research Program of China(973 Program)under Grant Nos 2011CBA00106 and2012CB927400the National Natural Science Foundation of China under Grant Nos 11274332 and 11227902Helmholtz Association through the Virtual Institute for Topological Insulators(VITI).M.Y.Li and D.W.Shen are also supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB04040300
文摘By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174124,11274068,11374137,11421404 and 13ZR1451700the National Basic Research Program of China(973 Program)under Grant No 2012CB921402
文摘We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, we identify the existence of the Fermi arcs originated from topological surface states. Furthermore, the surface states exhibit circular dichroism pattern, which may correlate with its non-trivial spin texture. Our results provide critical evidence for the existence of the Weyl Fermions in NbP, which lays the foundation for further research.
