相关论文: On the Switching between Negative and Positive The…
The negative thermal expansion (NTE) compound ZrW2O8 has been well-studied because it remains cubic with a nearly constant, isotropic NTE coefficient over a broad temperature range. However, its elastic constants seem just as strange as its…
The discovery of unusual negative thermal expansion (NTE) provides the opportunity to control the common but much desired property of thermal expansion, which is valuable not only in scientific interests but also in practical applications.…
Recently, uniaxial negative thermal expansion (NTE) has been observed in transition-metal zirconides including tetragonal (CuAl2-type) CoZr2 and orthorhombic (Re3B-type) CoZr3. Here, we report the observation of uniaxial NTE in tetragonal…
While most solids expand when heated, some materials show the opposite behavior: negative thermal expansion (NTE). In polymers and biomolecules, NTE originates from the entropic elasticity of an ideal, freely-jointed chain. The origin of…
We theoretically propose possible magnetism-induced negative thermal expansion in honeycomb-lattice antiferromagnets with edge-sharing networks of $MX_6$ octahedra where $M$ and $X$ are transition-metal and ligand ions, respectively. In…
We investigate detailed lattice dynamics of copper halides CuX (X=Cl, Br, I) using neutron inelastic scattering measurements and ab-initio calculations aimed at a comparative study of their thermal expansion behavior. We identify the low…
In the paper we report the modeling and design of material which has a negative thermal expansion (NTE). The basic assumption is a potential between the atoms in the material can be approximated by a Lennard-Jones potential (6-12) and the…
We consider the thermal expansion, change of sound velocity with pressure and temperature, and the Poisson ratio of lattices which have rigid units (polyhedra very large stiffness to change in bond-length and to bond-angle variations)…
Negative thermal expansion in ZrW2O8 was investigated using a flexibility analysis of ab-initio phonons. It was shown that no previously proposed mechanism adequately describes the atomic-scale origin of negative thermal expansion in this…
In this work, we study the thermo-mechanical behavior of metallic structures designed to significantly change shape in response to thermal stimuli. This behavior is achieved by arranging two metals with different coefficient of thermal…
Pressure and temperature dependence of the negative thermal expansion in Zn(CN)$_2$ is fully investigated using molecular dynamics simulations with a built potential model. The advantage of this study allows us to reproduce all the exotic…
The hydration and ammonization of ZrW2O8 is known to lead to positive and negative thermal expansion behaviour respectively. We report ab-initio calculations to understand this anomalous behaviour. We identify the crucial low energy phonon…
A limited number of 2D and 3D materials under a constant pressure contract in volume upon heating isobarically; this anomalous phenomenon is known as the negative thermal expansion (NTE). In this paper, the NTE anomaly is observed in 1D…
Previous experiments and numerical simulations have revealed that a limited number of two- and three-dimensional particle systems contract in volume upon heating isobarically. This anomalous phenomenon is known as negative thermal expansion…
The thermophysical properties of oxide scale, in the general case, are affected by the variation of the temperature of phase transitions (either magnetic or polymorphic) in its components due to impurities, lattice defects, grain sizes,…
Understanding the coupling between structural phase transitions and thermal transport is essential for designing functional materials with tunable properties. Here, we investigate this interplay in CaSnF$_6$ by combining first-principles…
In the fundamental understanding of magnetic interactions between atoms in solids, the crystal lattice is one of the key parameters. As the effective tool for controlling the lattice using tensile stress is limited, there are only few…
We find a design principle for tailoring thermal expansion properties in nearly-spherical molecular networks. Using 2D fullerene networks as a representative system, we realize positive thermal expansion along intermolecular [2\,+\,2]…
Organic charge transfer salts exhibit thermal expansion anomalies similar to those found in other strongly correlated electron systems. The thermal expansion can be anisotropic and have a non-monotonic temperature dependence. We show how…
The negative thermal expansion (NTE) effect has been found generally combined with structural phase transitions. However, the charge and orbital freedoms of the NTE has not been well studied. This study employs angle-resolved photoemission…