The Mechanism of Electrolyte Gating on High-T_c Cuprates: the Role of Oxygen Migration and Electrostatics

Electrolyte gating is widely used to induce large carrier density modulation on solid surfaces to explore various properties. However, its mechanism is still being debated, and it is therefore vital to reveal the relationship between the role of electrolyte gating and the intrinsic properties of materials. Here, we report entirely different mechanisms of electrolyte gating on two high-T_c cuprates, NdBa₂Cu₃O_7-δ (NBCO) and Pr_2-xCe_xCuO₄ (PCCO), with different crystal structures. We show that field-induced oxygen vacancy formation in CuO chains of NBCO plays the dominant role while it is mainly an electrostatic field effect in the case of PCCO. The possible reason is that NBCO has mobile oxygen in CuO chains while PCCO does not. Our study helps clarify the controversy relating to the mechanism of electrolyte gating, leading to a better understanding of the role of oxygen electro migration which is very material specific.

In collaboration with Lingchao Zhang, Xinmao Yin, Teguh Citra Asmara, Ping Yang, Kun Han, Yu Cao, Wenxiong Zhou, Dongyang Wan, Chi Sin Tang, Andrivo Rusydi