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The rare-earth tritellurides (RTe 3 ) are a distinct class of 2D layered materials that recently gained significant attention due to hosting such quantum collective phenomena as superconductivity or charge density waves (CDWs). Many members of this van der Waals (vdW) family crystals exhibit CDW behavior at room temperature, i.e. , RTe 3 compound where R = La, Ce, Pr, Nd, Sm, Gd, and Tb. Here, our systematic studies establish the CDW properties of RTe 3 when the vdW spacing/interaction strength between adjacent RTe 3 layers is engineered under extreme hydrostatic pressures. Using a non-destructive spectroscopy technique, pressure-dependent Raman studies first establish the pressure coefficients of phonon and CDW amplitude modes for a variety of RTe 3 materials, including LaTe 3 , CeTe 3 , PrTe 3 , NdTe 3 , SmTe 3 , GdTe 3 , and TbTe 3 . Results further show that the CDW phase is eventually suppressed at high pressures when the interlayer spacing is reduced and interaction strength is increased. Comparison between different RTe 3 materials shows that LaTe 3 with the largest thermodynamic equilibrium interlayer spacing (smallest chemical pressure) exhibits the most stable CDW phases at high pressures. In contrast, CDW phases in late RTe 3 systems with the largest internal chemical pressures are suppressed easily with applied pressure. Overall results provide comprehensive insights into the CDW response of the entire RTe 3 series under extreme pressures, offering an understanding of CDW formation/engineering in a unique class of vdW RTe 3 material systems.
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Assessment of Pressure and Density of Confined Water in Graphene Liquid Cells
Abstract Understanding the behavior of confined matter within Van der Waals (VdW) materials is complicated due to the interplay of various factors, including the VdW interaction between the interlayers, the layer interaction with the matter, and the bending strain energy of the layers to accommodate encapsulation. Herein, new insight on the magnitude of pressure and density of water entrapped within confined spaces in VdW materials is provided. This is accomplished by studying the plasmon excitation of water encapsulated between two sheets of graphene membranes in an aberration‐corrected scanning transmission electron microscope. The results indicate ≈12% maximum increase in the density of water under tight graphene encasement, where pressure as high as 400 MPa is expected. The pressure estimation from theoretical analysis considering the effect of VdW forces, Laplace pressure, and strain energy is in agreement with the experimental results. The findings of this work open new opportunities to explore the local physical state of not only water but also other liquid materials under high pressure with imaging and analytical resolutions never achieved before.
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- PAR ID:
- 10376670
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 7
- Issue:
- 12
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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