Role of Oxygen in Ionic Liquid Gating on Two-Dimensional Cr2

Dec 18, 2017 - Iwasa, Y. Superconducting Dome in a Gate-Tuned Band Insulator. .... Zhang, X. Discovery of intrinsic ferromagnetism in two-dimensional...
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Cite This: ACS Appl. Mater. Interfaces 2018, 10, 1383−1388

Role of Oxygen in Ionic Liquid Gating on Two-Dimensional Cr2Ge2Te6: A Non-oxide Material Yangyang Chen,†,‡,§ Wenyu Xing,†,‡,§ Xirui Wang,†,‡,§ Bowen Shen,†,‡ Wei Yuan,†,‡ Tang Su,†,‡ Yang Ma,†,‡ Yunyan Yao,†,‡ Jiangnan Zhong,†,‡ Yu Yun,†,‡ X. C. Xie,†,‡ Shuang Jia,*,†,‡ and Wei Han*,†,‡ †

International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, PR China Collaborative Innovation Center of Quantum Matter, Beijing 100871, PR China



ABSTRACT: Ionic liquid gating can markedly modulate a material’s carrier density so as to induce metallization, superconductivity, and quantum phase transitions. One of the main issues is whether the mechanism of ionic liquid gating is an electrostatic field effect or an electrochemical effect, especially for oxide materials. Recent observation of the suppression of the ionic liquid gate-induced metallization in the presence of oxygen for oxide materials suggests the electrochemical effect. However, in more general scenarios, the role of oxygen in the ionic liquid gating effect is still unclear. Here, we perform ionic liquid gating experiments on a non-oxide material: two-dimensional ferromagnetic Cr2Ge2Te6. Our results demonstrate that despite the large increase of the gate leakage current in the presence of oxygen, the oxygen does not affect the ionic liquid gating effect on the channel resistance of Cr2Ge2Te6 devices (