Pressure-induced band-gap closure and metallization in two-dimensional transition metal halide CdI2

Yan, Zhipeng; Yin, Ketao; Yu, Zhenhai; Li, Xin; Li, Mingtao; Yuan, Ye; Li, Xiaodong; Yang, Ke; Wang, Xiaoli; Wang, Lin

doi:10.1016/j.apmt.2019.100532

Cited by 12 publications

(11 citation statements)

References 38 publications

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“…Figure 2e presents the typical Raman spectra of CdI 2 flakes grown on mica substrate. Obviously, there are two prominent and strong characteristic peaks around 45 and 110 cm −1 , which correspond to the in-plane (E g ) and the out-of-plane (A 1g ) phonon vibration mode, respectively, in consist with the recently reported 2D CdI 2 crystals [43,44]. The inset is the representative Raman intensity maps of E g and A 1g modes of a typical CdI 2 triangular flake, indicating highly uniform crystalline quality throughout the entire flake.…”

Section: Growth and Characterization Of Layered CDI 2 Flakessupporting

confidence: 70%

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

et al. 2021

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Nonlayered two-dimensional (2D) materials have attracted increasing attention, due to novel physical properties, unique surface structure, and high compatibility with microfabrication technique. However, owing to the inherent strong covalent bonds, the direct synthesis of 2D planar structure from nonlayered materials, especially for the realization of large-size ultrathin 2D nonlayered materials, is still a huge challenge. Here, a general atomic substitution conversion strategy is proposed to synthesize large-size, ultrathin nonlayered 2D materials. Taking nonlayered CdS as a typical example, large-size ultrathin nonlayered CdS single-crystalline flakes are successfully achieved via a facile low-temperature chemical sulfurization method, where pre-grown layered CdI2 flakes are employed as the precursor via a simple hot plate assisted vertical vapor deposition method. The size and thickness of CdS flakes can be controlled by the CdI2 precursor. The growth mechanism is ascribed to the chemical substitution reaction from I to S atoms between CdI2 and CdS, which has been evidenced by experiments and theoretical calculations. The atomic substitution conversion strategy demonstrates that the existing 2D layered materials can serve as the precursor for difficult-to-synthesize nonlayered 2D materials, providing a bridge between layered and nonlayered materials, meanwhile realizing the fabrication of large-size ultrathin nonlayered 2D materials.

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Section: Growth and Characterization Of Layered CDI 2 Flakessupporting

confidence: 70%

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

et al. 2021

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“…Thus, their structural responses and physical and chemical properties may differ while under compression at high pressure (HP). For example, at high pressure, the metallic-like graphite can be turned into insulating diamond, whereas insulating/semiconducting compounds can be turned into metallic (e.g., CrPS 4 ) − and even superconducting states (e.g., FePSe 3 and CrSiTe 3 ). , At high pressure, 2D-vdW materials can also be turned into bulk (or bulk-like) vdW materials via strong coupling of the vdW layers. − This would produce significant modifications of the physical chemical properties present initially in the 2D materials.…”

Section: Introductionmentioning

confidence: 99%

“…It is apparent that, by changing the chemical composition and/or external pressure, the structures and properties of vdW materials can be modified significantly. For this reason, layered 2D materials such as graphene, transition metal dichalcogenides, , metal phosphorus trichalcogenides, ,, transition metal dihalides, and bismuth oxyhalides , have been studied extensively at high pressures. It is noteworthy that the element copper was not concerned in these prior studies.…”

Section: Introductionmentioning

confidence: 99%

Metallization and Superconductivity in the van der Waals Compound CuP₂Se through Pressure-Tuning of the Interlayer Coupling

Feng

Zhang

et al. 2021

J. Am. Chem. Soc.

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Emergent layered Cu-bearing van der Waals (vdW) compounds have great potentials for use in electrocatalysis, lithium batteries, and electronic and optoelectronic devices. However, many of their alluring properties such as potential superconductivity remain unknown. In this work, using CuP2Se as a model compound, we explored its electrical transport and structural evolution at pressures up to ∼60 GPa using both experimental determinations and ab initio calculations. We found that CuP2Se undergoes a semiconductor-to-metal transition at ∼20 GPa at room temperature and a metal-to-superconductor transition at 3.3–5.7 K in the pressure range from 27.0 to 61.4 GPa. At ∼10 and 20 GPa, there are two isostructural changes in the compound, corresponding to, respectively, the emergence of the interlayer coupling and start of interlayer atomic bonding. At a pressure between 35 and 40 GPa, the vdW layers start to slide and then merge, forming a new phase with high coordination numbers. We also found that the Bardeen–Cooper–Schrieffer (BCS) theory describes quite well the pressure dependence of the critical temperature despite occurrence of a possible medium-to-strong electron–phonon coupling, revealing the determinant roles of the enhanced bulk modulus and electron density of states at high pressure. Moreover, nanosizing of CuP2Se at high pressure further increased the critical temperature even at sizes approaching the Anderson limit. These findings would have important implications for developing novel applications of layered vdW compounds through simple pressure tuning of the interlayer coupling.

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“…In a word, the metallization appears through engineering vdW interactions, which provides an effective route to modulate the electrical band structure, enabling the tuning of spin properties and the electronic state of VS 2 . [11,172] Until now, the state transitions from an insulator or semiconductor state to the metallic state in various materials involving CdI 2 , [174] Bi 2 X 3 , Sb 2 X 3 , and Ag 2 X (e.g., X = S, Se, and Te), MOF, [44] perovskites, [39][40][41][42][43] BP, [32] etc., [20] have been investigated. In these metallizations, the large structural reconstructions or atomic movements mostly take place to close the vdW gaps or lead to first-order structural transitions although the unique metallization of hybrid perovskites without structural transition has been found.…”

Section: Metallizationmentioning

confidence: 99%

“…It shows a slow-down drop of resistance and a tendency toward a low-temperature curve with the increase of magnetic fields, proving the emergence of the superconducting phase. [180] Chi et al also investigated the www.advancedsciencenews.com www.advancedscience.com [39] (CH 3 NH 3 )PbI 3 Above 60 (RT) [42] Cs 3 Bi 2 I 9 28 (338 K) [ 200] 2D TMDs ZrTe 2 T-ZrTe 2 ≈ 2 (H-Zr-Te 2 ≈ 6) [ 201] 1T-TiSe 2 2-4 (1.8 K) [ 191] WTe 2 10.5 (2.8 K); [ 183] 4-5 (300 K) [ 184] WS 2 22 (280 K) [17] WSe 2 51.7 (RT) [ 202] ZrS 2 5.6-25 [ 186] 5.6-25 (1.1-1.9 K) or 25-100 (0.3-0.1 K) [ 186] MoTe 2 14.9 [ 203] MoS 2 30 (270 K); [ 167] 9 (RT) [19] 90 (3 K) [ 167] Intermediate state: 10-19; semiconducting state: 0-10 [19] CdI 2 62 (240 K) [ 174] 35 (270 K) [ 174] semiconducting phase FeCL 2 47 (300 K) [ 204] NI 2 19 (310 K) [ 205] MgC 2 Ambient pressure (15 K) [ 206] BP 1.7, 10 [ 207] Above 5 (6-13 K); [ 181] above 10 (5-10 K); [ 182] 11-30 (4-10.7 K), 15 (6 K) [ 207] MoSe 2 40.7-60 [20] 0-40.7 semiconducting phase CaC 2 43 (7.9 K) and 95 (9.8 K) [ 185] CaC 6 7.5 (15.1 K) [ 208] superconductivity in pristine 2H a -MoS 2 and this is explained by the occurrence of a new flat Fermi pocket at ultrahigh pressure. [167] Using the external magnetic field, superconductivity was again verified.…”

Section: Superconductingmentioning

confidence: 99%

2D Materials and Heterostructures at Extreme Pressure

et al. 2020

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2D materials possess wide-tuning properties ranging from semiconducting and metallization to superconducting, etc., which are determined by their structure, empowering them to be appealing in optoelectronic and photovoltaic applications. Pressure is an effective and clean tool that allows modifications of the electronic structure, crystal structure, morphologies, and compositions of 2D materials through van der Waals (vdW) interaction engineering. This enables an insightful understanding of the variable vdW interaction induced structural changes, structure-property relations as well as contributes to the versatile implications of 2D materials. Here, the recent progress of high-pressure research toward 2D materials and heterostructures, involving graphene, boron nitride, transition metal dichalcogenides, 2D perovskites, black phosphorene, MXene, and covalent-organic frameworks, using diamond anvil cell is summarized. A detailed analysis of pressurized structure, phonon dynamics, superconducting, metallization, doping together with optical property is performed. Further, the pressure-induced optimized properties and potential applications as well as the vision of engineering the vdW interactions in heterostructures are highlighted. Finally, conclusions and outlook are presented on the way forward.

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Pressure-induced band-gap closure and metallization in two-dimensional transition metal halide CdI2

Cited by 12 publications

References 38 publications

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

Metallization and Superconductivity in the van der Waals Compound CuP₂Se through Pressure-Tuning of the Interlayer Coupling

2D Materials and Heterostructures at Extreme Pressure

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Pressure-induced band-gap closure and metallization in two-dimensional transition metal halide CdI2

Cited by 12 publications

References 38 publications

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large-Size Ultrathin Nonlayered Two-Dimensional Materials

Metallization and Superconductivity in the van der Waals Compound CuP2Se through Pressure-Tuning of the Interlayer Coupling

2D Materials and Heterostructures at Extreme Pressure

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Metallization and Superconductivity in the van der Waals Compound CuP₂Se through Pressure-Tuning of the Interlayer Coupling