Related papers: First-principles studies for structural transition…
We model the quasicrystal-related structure CaCd$_6$, a bcc packing of icosahedral clusters containing tetrahedra which undergo orientational orderings at T<100 K. We use general schemes to evaluate an effective Hamltonian for…
The dynamic orientational order-disorder transition of clusters consisting of octahedral molecules is formulated in terms of symmetry-adapted rotator functions. The transition from a higher-temperature body-centered-cubic, orientationally…
The orientational correlation scheme introduced earlier for tetrahedral molecules is extended for being able to classify orientational correlations between pairs of high symmetry molecules. While in the original algorithm a given…
The methyl groups in hexamethylbenzene C$_6$(CH$_3$)$_6$ become magnetically ordered at the molecular level below 118 K. This is also near the temperature at which the system structurally transitions from triclinic to a unique near-cubic…
Recent experiments discovered an order-disorder transition occuring at low temperatures in large unit 1/1 cell cubic approximants of the stable Cd-based binary alloy quasicrystals. The transition is related to correlations among…
In this paper we propose a tight-binding molecular dynamics with parameters fitted to first-principles calculations on the smaller clusters and with an environment correction, to be a powerful technique for studying large transition/noble…
For temperatures above $T^*=130$K C$_{60} \cdot$C$_8$H$_8$ forms a cubic crystal consisting of two interpenetrating fcc sublattices, one of freely rotating Buckys C$_{60}$ and the other of orientationally ordered cubane C$_8$H$_8$. The…
In this report, the evolution of the local atomic structure of the Zr50Nb50 melt was investigated by applying temperature (2600 to 300 K) and pressure (0 to 50 Gpa) using classical molecular dynamics simulations. To gain clear insight into…
Configurationally disordered crystalline boron carbide, B$_{4}$C, is studied using first-principles calculations. We investigate both dilute and high concentrations of carbon-boron substitutional defects. For the latter purpose, we suggest…
We investigate the interplay of the electronic and structural transition in La$_{0.2}$Sr$_{0.8}$MnO$_{3}$. The transport and specific heat measurements exhibit unusual evolutions and signature of a first order phase transition around 265 K.…
The temperature evolution of icosahedral medium-range order formed by interpenetrating icosahedra in CuZr metallic glass-forming liquids was investigated via molecular dynamics simulations. Scaling analysis based on percolation theory was…
TbFe$_{2}$D$_{4.2}$ deuteride crystallizes in a monoclinic structure ($Pc$ space group) with deuterium inserted into 13 [Tb$_{2}$Fe$_{2}$] and 5 [TbFe$_{3}$] tetrahedral interstitial sites. Its structural evolution versus temperature has…
A series of electronic and structural transitions are predicted in molten lithium from first principles. A new phase with tetrahedral local order characteristic of $sp^3$ bonded materials and poor electrical conductivity is found at…
We investigated structural changes, phase diagram, and vibrational properties of hydrogen hydrate in filled-ice phase C2 by using first principles molecular dynamics simulation. It was found that the experimentally reported 'cubic'…
A sequence of structural transitions occurring in the quasi-one-dimensional (1D) 3d1 system BaVS3 at low temperature was investigated by high resolution synchrotron X-ray diffraction. The orthorhombic Cmc21 structure of the…
A link between structural ordering and slow dynamics has recently attracted much attention from the context of the origin of glassy slow dynamics. Candidates for such structural order are icosahedral, exotic amorphous, and crystal-like.…
Y$_{0.9}$Gd$_{0.1}$Fe$_{2}$, which crystallizes in a C15 cubic structure, can absorb up to 5 H/f.u. and its pressure-composition isotherm displays a multiplateau behavior related to the existence of several hydrides with different crystal…
The Cudaca system composed of isolated Cu2+ S=1/2 tetrahedra with antiferromagnetic exchange should exhibit properties of a frustrated quantum spin system. ab initio density functional theory calculations for electronic structure and…
It is shown that the rotational band structure of the cluster states in 12C and 16O can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral…
We have used molecular dynamics simulations to construct a microcanonical caloric curve for a 1415-atom Ni icosahedron. Prior to melting the Ni cluster exhibits static solid-liquid phase coexistence. Initially a partial icosahedral…