Phase transition of solid-state materials is a fundamental research topic in condensed matter physics, materials science and geophysics. It has been well accepted and widely proven that isostructural compounds containing different cations undergo same pressure-induced phase transitions but at progressively lower pressures as the cation radii increases. However, we discovered that this conventio...

In this work, we report our results on the phase transition of a flexible homopolymer from a stretched chain to a compact globule. The Wang-landau method is used to study the thermodynamic properties of a the chain up to 512 monomers. We believe that the peak in the specific heat at low temperature T ≈ 0.05 for small chain sizes N < 100 is a clear evidence of the existence of metastable helical...

To overcome these problems, very effective diffusion barriers need to be developed. These barriers should have a low diffusivity for copper, a high thermal stability, and should lack a driving force for chemical reactions with Cu, silicon or silicides. Unlike aluminum, copper does not form stable intermetallic compounds with the transition metals of the V and Cr groups, and the mutual solid sol...

We find numerically that the sample to sample fluctuation of the entropy DeltaS is a more sensitive tool in distinguishing low from high temperature behaviors than the common corresponding fluctuation in the free energy. In 1+1 dimensions we find a single phase for all temperatures, since (DeltaS)(2) is always extensive. In 2+1 dimensions we find a behavior that at first sight might appear to b...

Pairing transition at finite temperature was investigated by the shell model and BCS calculations. The definitive signature of pairing transition is identified by a “transition temperature” Tt estimated from a “thermal” odd-even mass difference, while there is no sharp phase transition because of the finiteness of nucleus. It is found that Tt is in good agreement with predictions of critical te...

4-ChloroMethyl Styrene (CMS) was copolymerized with different monomers such as Methyl MethAcrylate (MMA), Methyl Acrylate (MA), 2-EthylHexyl Acrylate (EHA) by free radical polymerization method at 70 ±1°C using a,a'-Azobis(IsoButyroNitrile) (AIBN) as an initiator. The copolymer compositions were obtained using related 1HNMR spectra and the poly...

The properties of compressed liquid hydrogen, the most abundant fluid in the universe, have been investigated by means of first-principles molecular dynamics at pressures between 75 and 175 GPa and temperatures closer to the freezing line than so far reported in shock-wave experiments. Evidence for a liquid-liquid transition between a molecular and a dissociated phase is provided. The transitio...

Experimental Raman and IR spectra of multiferroic [(CH3)2NH2][Ni(HCOO)3] were recorded at room temperature. The three-parameter hybrid B3LYP density functional method has been used with the 6-31G(d, p) basis set to derive the equilibrium geometry, atomic spin densities, vibrational wavenumbers, infrared intensities and Raman scattering activities. Based on these calculations, the assignment of ...

2014 X-ray diffuse scattering studies of one dimensional conductors (TMTSF)2ReO4 and (TMTSF)2NO3 reveal the formation of low temperature superstructures which might involve an ordering of the counter ions ReO-4 and NO-3. The superstructure reflections are characterized by wave vectors q = (1/2, 1/2, 1/2) for the perrhenate and q = (1/2, 0, 0) for the nitrate, which double the unit cell volume i...

Dynamical mean-field theory and its cluster extensions provide a very useful approach for examining phase transitions in model Hamiltonians and, in combination with electronic structure theory, constitute powerful methods to treat strongly correlated materials. The key advantage to the technique is that, unlike competing real-space methods, the sign problem is well controlled in the Hirsch-Fye ...