Related papers: Polymorphism in $\alpha$-sexithiophene crystals: R…
Understanding phase transitions between crystalline phases of a material is crucial for both fundamental research and potential applications such as phase-change memory. In this study, we investigate the phase transition between GeSe…
Lattice thermal conductivities (LTC) for a subset of polymer crystals from the Polymer Genome Library were investigated to explore high LTC polymer systems. We employed a first-principles approach to evaluating phonon lifetimes within the…
With few systems of technological interest having been studied as extensively as elemental silicon, there currently exists a wide disparity between the number of predicted low-energy silicon polymorphs and those, which have been…
Crystals form regular and robust structures that under extreme conditions can melt and recrystallize into different arrangements in a process that is called crystal metamorphism. While crystals exist due to the breaking of a continuous…
We investigate domain formation and local morphology of thin films of $\alpha$-sexithiophene ($\alpha$-6T) on Au(100) beyond monolayer coverage by combining high resolution scanning tunneling microscopy (STM) experiments with electronic…
The VO2 polymorphs, i.e., VO2(A), VO2(B), VO2(M1) and VO2(R), have a wide spectrum of functionalities useful for many potential applications in information and energy technologies. However, synthesis of phase pure materials, especially in…
We have performed a combined experimental and theoretical study of ethane and methane at high pressures up to 120 GPa at 300 K using x-ray diffraction and Raman spectroscopy and the USPEX ab-initio evolutionary structural search algorithm,…
We have performed high-pressure, electrical resistivity, and specific heat measurements on CeTe3 single crystals. Two magnetic phases with nonparallel magnetic easy axes were detected in electrical resistivity and specific heat at low…
The temperature dependance of the action in the thin-wall and thick-wall limits is obtained analytically for the $\phi^6$ scalar potential. The nature of the phase transition is investigated from the quantum tunnelling regime at low…
The phase transitions between the various polymorphs of FAPbI$_{3}$ (FAPI, FA = formamidinium CH(NH$_{2}$)$_{2}^+$) are studied by anelastic, dielectric and X--ray diffraction measurements on samples pressed from $\delta -$FAPI (2H phase)…
Diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate, [PF$_6$][P$_{1,2,2,4}$], is an organic ionic plastic crystal with potential uses as a solid electrolyte in storage and light harvesting devices. In this work we present a molecular…
Heat transport can be modelled with a variety of approaches in real space (using molecular dynamics) or in reciprocal space (using the Boltzmann transport equation). Employing two conceptually different approaches of each type, we study…
We report on sexithiophene films, about 150nm thick, grown by thermal evaporation on single crystal oxides and, as comparison, on Si/SiO2. By heating the entire deposition chamber at 100 C we obtain standing-up oriented molecules all over…
The phase diagram of oxygen is investigated for pressures from 50 to 130~GPa and temperatures up 1200 K using first principles theory. A metallic molecular structure with the $P6_3/mmc$ symmetry ($\eta^{'}$ phase) is determined to be…
Pentacene crystallizes in a layered structure with a herringbone arrangement within the layers. The electronic properties depend strongly on the stacking of the molecules within the layers (Haddon et al., 2002). We have synthesized four…
Halide perovskites, with prototype cubic phase ABX3, undergo various phase transitions accompanied by rigid rotations of corner-sharing BX6 octahedra. Using first-principles density functional theory calculations, we have performed a…
The microscopic model of semi-crystalline polymer in high-elastic state is proposed. The model is based on the assumption that, below the melting temperature, the semi-crystalline polymer comprises crystal nuclei connected by stretched…
High transition temperature (high-Tc) superconductivity is associated with layered crystal structures. This work considers superconductivity in ultra-thin crystals (of thickness equal to the transverse structural periodicity distance d for…
The relative stability of SiC polytypes, changing with temperature, has been considered a paradox for about thirty years, due to discrepancies between theory and experiments. Based on ab-initio calculations including van der Waals…
SiC polytypes have been studied for decades, both experimentally and with atomistic simulations, yet no consensus has been reached on the factors that determine their stability and growth. Proposed governing factors are…