Temperature Dependent Structural Evolution of WSe2: A Synchrotron X-ray Diffraction Study

Mathew, S.; Abraham, Aben Regi; Chintalapati, Sandhya; Sarkar, Soumya; Joseph, Boby; Venkatesan, T.

doi:10.3390/condmat5040076

Cited by 21 publications

(13 citation statements)

References 26 publications

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“…The available data cover the temperature interval of 10-1000 K, which enables a second-order expansion of the Grüneisen approximation. In this method, the anharmonic contributions from the lattice vibration are considered and the thermal expansion of the unit-cell volume V(T) has a similar description to the elastic strain and can be second-order expanded, as follows [30][31][32]:…”

Section: Thermoelastic Propertiesmentioning

confidence: 99%

Thermal Expansion and Rattling Behavior of Gd-Filled Co4Sb12 Skutterudite Determined by High-Resolution Synchrotron X-ray Diffraction

et al. 2022

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In this work, Gd-filled skutterudite GdxCo4Sb12 was prepared using one step method under high pressure in a piston-cylinder-based press at 3.5 GPa and moderate temperature of 800 °C. A detailed structural characterization was performed using synchrotron X-ray diffraction (SXRD), revealing a filling fraction of x = 0.033(2) and an average <Gd–Sb> bond length of 3.3499(3) Å. The lattice thermal expansion accessed via temperature-dependent SXRD led to a precise determination of a Debye temperature of 322(3) K, from the fitting of the unit-cell volume expansion using the second order Grüneisen approximation. This parameter, when evaluated through the mean square displacements of Co and Sb, displayed a value of 265(2) K, meaning that the application of the harmonic Debye theory underestimates the Debye temperature in skutterudites. Regarding the Gd atom, its intrinsic disorder value was ~5× and ~25× higher than those of the Co and Sb, respectively, denoting that Gd has a strong rattling behavior with an Einstein temperature of θE = 67(2) K. As a result, an ultra-low thermal conductivity of 0.89 W/m·K at 773 K was obtained, leading to a thermoelectric efficiency zT of 0.5 at 673 K.

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Section: Thermoelastic Propertiesmentioning

confidence: 99%

Thermal Expansion and Rattling Behavior of Gd-Filled Co4Sb12 Skutterudite Determined by High-Resolution Synchrotron X-ray Diffraction

et al. 2022

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“…Intriguingly, the expansion along the c-axis is much more insensitive to that along the a-axis, probably because the B−W−B intralayer is more sensitive to temperature, in contrast to that of the interlayers. Besides, the determined Debye temperature (θ D ) 49 for WB 2+x is 730 K (Figure S8), close to WC (i.e., 621 K), 50 suggesting its strong interatomic force and excellent mechanical properties.…”

Section: ■ Experimental Sectionmentioning

confidence: 85%

Synthesis, Phase Evolutions, and Stabilities of Boron-Rich Tungsten Borides at High Pressure

Zhou

et al. 2022

Inorg. Chem.

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Boron-rich tungsten borides such as WB2+x and WB3+x have been highly expected to be superhard with many advantages over conventional superhard materials. However, because the formation of boron-rich tungsten borides is thermodynamically unfavorable at ambient pressure, their crystal structures, compositions, and properties are largely unexplored, which have impeded the rational design of functional materials in the W–B family. In this work, using unique high-pressure reactions, we report a systematic synthesis study of challenging compounds of tungsten borides including WB, WB2+x , and WB3+x . The use of pressure, combined with the controllable temperature, heating duration, and ratios of starting reactants, leads to different compositions and structures of final products with largely tunable crystallite size from nanocrystalline to single-crystal forms. In addition, the optimal conditions for the formation of WB3+x are well investigated by tuning the temperature and starting ratio of reactants, as well as by adding a solvent material. Phase diagrams and stabilities of the involved W–B compounds are also well depicted, which would provide an important guidance for future exploratory synthesis and study of the family of transition-metal borides.

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“…In the case of electrical actuation ( 46 ), Joule heating from a back-gate voltage can cause an oscillating temperature of ΔT . Such oscillation imposes a cyclic eigenstrain on the suspended monolayer, which results in an oscillating stress

( 47 , 48 ). At the same time, there is typically a prestress within the monolayer

( 47 ) caused by its adhesion with the substrate and averaged operating temperature.…”

Section: Discussionmentioning

confidence: 99%

Atomistic measurement and modeling of intrinsic fracture toughness of two-dimensional materials

Zhang

Nguyen

Zhang

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Quantifying the intrinsic mechanical properties of two-dimensional (2D) materials is essential to predict the long-term reliability of materials and systems in emerging applications ranging from energy to health to next-generation sensors and electronics. Currently, measurements of fracture toughness and identification of associated atomistic mechanisms remain challenging. Herein, we report an integrated experimental–computational framework in which in-situ high-resolution transmission electron microscopy (HRTEM) measurements of the intrinsic fracture energy of monolayer MoS 2 and MoSe 2 are in good agreement with atomistic model predictions based on an accurately parameterized interatomic potential. Changes in crystalline structures at the crack tip and crack edges, as observed in in-situ HRTEM crack extension tests, are properly predicted. Such a good agreement is the result of including large deformation pathways and phase transitions in the parameterization of the inter-atomic potential. The established framework emerges as a robust approach to determine the predictive capabilities of molecular dynamics models employed in the screening of 2D materials, in the spirit of the materials genome initiative. Moreover, it enables device-level predictions with superior accuracy (e.g., fatigue lifetime predictions of electro- and opto-electronic nanodevices).

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Temperature Dependent Structural Evolution of WSe2: A Synchrotron X-ray Diffraction Study

Cited by 21 publications

References 26 publications

Thermal Expansion and Rattling Behavior of Gd-Filled Co4Sb12 Skutterudite Determined by High-Resolution Synchrotron X-ray Diffraction

Thermal Expansion and Rattling Behavior of Gd-Filled Co4Sb12 Skutterudite Determined by High-Resolution Synchrotron X-ray Diffraction

Synthesis, Phase Evolutions, and Stabilities of Boron-Rich Tungsten Borides at High Pressure

Atomistic measurement and modeling of intrinsic fracture toughness of two-dimensional materials

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