Title: The Mechanism of Electrolyte Gating on High-Tc Cuprates: The Role of Oxygen Migration and Electrostatics,
Abstract: Electrolyte gating is widely used to induce large carrier density modulation
on solid surfaces to explore various properties. Most of past works have
attributed the charge modulation to electrostatic field effect. However, some
recent reports have argued that the electrolyte gating effect in VO2, TiO2 and
SrTiO3 originated from field-induced oxygen vacancy formation. This gives rise
to a controversy about the gating mechanism, 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-Tc cuprates, NdBa2Cu3O7-{\delta}
(NBCO) and Pr2-xCexCuO4 (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.