Tuning the Electronic Structure of Sr2IrO4 Thin Films by Bulk Electronic Doping Using Molecular Beam Epitaxy

• Published in: 中国物理快报：英文版 2015-05 (5), p.124-128
• Main Author: 李明颖 刘正太 杨海峰 赵家琳 姚岐 樊聪聪 刘吉山 高波 沈大伟 谢晓明
• Format: Article
• Language: English
• Subjects: 兴奋剂; 分子束外延; 单晶薄膜; 电子掺杂; 电子结构; 角分辨光电子能谱; 调整; 费米能级
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/32/5/057402

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.