Manipulation of 2DEG at double-doped high-entropy heterointerfaces.

Chemical doping is a dominating method for manipulating oxide two-dimensional electron gas (2DEG). However, enhancing the doping level while maintaining the metallic conduction remains a challenge, which limits detailed knowledge of 2DEG manipulation. Herein, we propose a concept of high-entropy heterointerface, which consists of a complex oxide (containing at least 5 elements) at either or both sides of the interface. By doubly doping Sr and Mn elements in the Nd and Al sites of NdAlO 3 , we grow Nd 1- x Sr x Al 1- x Mn x O 3 (NSAMO) films onto SrTiO 3 (STO) substrates to fabricate NSAMO/STO high-entropy heterointerfaces with different thicknesses (2-30 nm) and a wide range of doping ratios x (0.14-0.56). The 2DEG conducting behavior is maintained until x = 0.42, which is higher compared with similar studies. The varying x results in the coexistence of rich properties like a weak anti-localization (0.14-0.42), abnormal Hall effect (0.28 & 0.42), Lifshitz transition (0.42) and stable structure. These results confirm the potential of this strategy to tailor 2DEG in all-oxide interfaces.