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Nat Nanotechnol. 2015 Mar;10(3):270-6. doi: 10.1038/nnano.2014.323. Epub 2015 Jan 26.

Gate-tunable phase transitions in thin flakes of 1T-TaS2.

Author information

1
1] State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China [2] Collaborative Innovation Center of Advanced Microstructures, 22 Hankou Road, Gulou, Nanjing 210093, China.
2
1] Collaborative Innovation Center of Advanced Microstructures, 22 Hankou Road, Gulou, Nanjing 210093, China [2] Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China [3] Key Laboratory of Strongly Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
3
1] State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China [2] Collaborative Innovation Center of Advanced Microstructures, 22 Hankou Road, Gulou, Nanjing 210093, China [3] Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
4
Laboratory for Pohang Emergent Materials and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea.
5
Korea Institute for Advanced Study, Hoegiro 87, Dongdaemun-gu, Seoul, Korea.
6
1] Laboratory for Pohang Emergent Materials and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea [2] Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.

Abstract

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.

PMID:
25622230
DOI:
10.1038/nnano.2014.323

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