Ion-Liquid-Gated KTaO 3 -Based Electric Double Layer Transistor

The electric double layer transistor (EDLT) based on the two-dimensional electron gases (2DEGs) at the LaAlO $_{\mathbf {{3}}}$ /KTaO $_{\mathbf {{3}}}$ (LAO/KTO) interface is fabricated. Using the ionic liquid gating (ILG), we increase the carrier density of 2DEGs from $2.49\times 10^{\mathbf {{13}}}$ to $4.37\times 10^{\mathbf {{13}}}$ cm $^{\mathbf {-{2}}}$ and Hall mobility from 140 to 229 cm $^{\mathbf {{2}}}\,\,\cdot \,\,\text{V}^{\mathbf {-{1}}}\,\,\cdot \,\,\text{s}^{\mathbf {-{1}}}$ at 5 K by sweeping gate voltage from −2.5 to 3 V. Meanwhile, the gate-tunable Kondo effect is observed once the carrier density at 5 K is lower than the critical value of $3.08\times 10^{\mathbf {{13}}}$ cm $^{\mathbf {-{2}}}$ . Notably, the Rashba spin-orbit coupling of 2DEGs is further regulated by the ILG with the largest spin-splitting energy of 25.42 meV. These results suggest that the ILG serves as a powerful technique to explore the unprecedented properties of KTO-based 2DEGs and design the EDLT devices with superior performances.