Gate-tunable phase transitions in thin flakes of 1T-TaS2
Gate-tunable phase transitions in thin flakes of 1T-TaS2
复制标题
1T-TaS2 薄片中的栅极可调相变
DOI：
10.1038/nnano.2014.323
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发表时间：
2015-03-15
影响因子：
38.3
通讯作者：
Zhang, Yuanbo
中科院分区：
文献类型：
--
作者：
Yu, Yijun;Yang, Fangyuan;Zhang, Yuanbo
利用电场选通来调整材料特性的能力是现代电子技术的核心。它也是最近二维系统进展背后的驱动力，例如观察到栅极电场诱导的超导性和金属-绝缘体转变。在这里，我们描述了一种离子场效应晶体管（称为iFET），其中栅极控制的锂离子嵌入调制1 T-TaS 2的层状晶体的材料特性。可调离子嵌入引起的强电荷掺杂改变了1 T-TaS 2中各种电荷有序态的能量学，并在具有降低维数的薄片样品中产生一系列相变。我们发现1 T-TaS_2中的电荷密度波态在临界厚度下在二维极限下发生坍缩。同时，在低温下，离子门诱导从莫特绝缘体到金属的1 T-TaS 2薄片的多个相变，具有5个数量级的电阻调制，和超导电性出现在纹理电荷密度波状态诱导的离子门。我们的门控嵌入方法为在极端电荷载流子浓度极限下寻找新的物质状态开辟了可能性。
The ability to tune material properties using gating by electric fields is at the heart of modern electronic technology. It is also a driving force behind recent advances in two-dimensional systems, such as the observation of gate electric-field-induced superconductivity and metal-insulator transitions. Here, we describe an ionic field-effect transistor (termed an iFET), in which gate-controlled Li ion intercalation modulates the material properties of layered crystals of 1T-TaS2. The strong charge doping induced by the tunable ion intercalation alters the energetics of various charge-ordered states in 1T-TaS2 and produces a series of phase transitions in thin-flake samples with reduced dimensionality. We find that the charge-density wave states in 1T-TaS2 collapse in the two-dimensional limit at critical thicknesses. Meanwhile, at low temperatures, the ionic gating induces multiple phase transitions from Mott-insulator to metal in 1T-TaS2 thin flakes, with five orders of magnitude modulation in resistance, and superconductivity emerges in a textured charge-density wave state induced by ionic gating. Our method of gate-controlled intercalation opens up possibilities in searching for novel states of matter in the extreme charge-carrier-concentration limit.