Figure 1
From: Oxygen Displacement in Cuprates under Ionic Liquid Field-Effect Gating
In-situ structural investigations of electrolyte-gated La1.96Sr0.04CuO4 thin film epitaxially grown on a LaSrAlO4 (LSAO) substrate.
(a) Schematics of in-situ surface X-ray diffraction measurements and ionic-liquid gating experimental setup. Ki and Kf are incident and diffracted beam vectors, respectively. The bias voltage is applied between a contact wire bonded to the sample surface (ground) and Pt wire (gate) during ionic liquid gating operation. (b) The diffraction intensity along the (1 0 L) non-specular Bragg rod with the variation of bias voltage conditions. Blue: pristine sample; red: under open-circuit condition; magenta: under Vg = 3.2 V bias. The curves have been displaced for clarity. The reciprocal lattice unit (r.l.u.) in the film = 4.78 nm−1. (c) Blue open circles with line: the diffraction intensity measured along a representative specular Bragg rod of the La1.96Sr0.04CuO4 thin film epitaxially grown on a LaSrAlO4 substrate. Red solid line the diffraction intensity calculated from the COBRA-determined electron density. (d) Half crystallographic unit cell with the equatorial oxygen atoms in the CuO2 plane labelled OP and the apical oxygens labelled OA.
