ON the Nature of Ionic Liquid Gating of La(2−x)Sr(x)CuO(4)

Ionic liquids have recently been used as means of modulating the charge carrier properties of cuprates. The mechanism behind it, however, is still a matter of debate. In this paper we report experiments on ionic liquid gated ultrathin La(2−x)Sr(x)CuO(4) films. Our results show that the electrostatic part of gating has limited influence in the conductance of the cuprate in the gate voltage range of 0 to [Formula: see text] V. A non-electrostatic mechanism takes over for gate voltages below [Formula: see text] V. This mechanism most likely changes the oxygen concentration of the film. The results presented are in line with previous X-ray based studies on ionic liquid gating induced oxygenation of the cuprate materials YBa(2)Cu(3)O(7−x) and La(2−x)Sr(x)CuO(4).