We report the magnetization, specific heat, and transport measurements of a high quality Na(0.85)CoO2 single crystal in applied magnetic fields up to 14 T. At high temperatures, the system is in a paramagnetic phase. It undergoes a magnetic phase transition below approximately 20 K. For the field H||c, the measurement data of magnetization, specific heat, and magnetoresistance reveal a metamagn...

Using first-principles simulations, we identify the microscopic origin of the nonlinear dielectric response and high energy density of polyvinylidene-fluoride-based polymers as a cooperative transition path that connects nonpolar and polar phases of the system. This path explores a complex torsional and rotational manifold and is thermodynamically and kinetically accessible at relatively low te...

In this paper we investigate the ground state and the nature of the transition from an orientational ordered phase at low temperature to the disordered state at high temperature in a molecular crystal. Our model is a Potts model which takes into account the exchange interaction J between nearest-neighbor molecules and a dipolar interaction between molecular axes in three dimensions. The dipolar...

A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin-valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate...

Growing network models with both heterogeneity of the nodes and topological constraints can give rise to a rich phase structure. We present a simple model based on preferential attachment with rewiring of the links. Rewiring probabilities are modulated by the negative fitness of the nodes and by the constraint for the network to be a simple graph. At low temperatures and high rewiring rates, th...

Using Monte Carlo simulations, we study a coarse-grained model of a water layer confined in a fixed disordered matrix of hydrophobic nanoparticles at different particle concentrations c. For c=0, we find a first-order liquid-liquid phase transition (LLPT) ending in one critical point at low pressure P. For c>0, our simulations are consistent with a LLPT line ending in two critical points at low...

We perform molecular dynamics simulations of 512 waterlike molecules that interact via the TIP5P potential and are confined between two smooth hydrophobic plates that are separated by 1.10 nm. We find that the anomalous thermodynamic properties of water are shifted to lower temperatures relative to the bulk by approximately 40 K. The dynamics and structure of the confined water resemble bulk wa...

In this thesis I will discuss the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating a direction of alignment for the low-temperature nematic phase. Shear flow...

The holographic dual of a finite-temperature gauge theory with a small number of flavors typically contains D-brane probes in a black hole background. At low temperature, the branes sit outside the black hole and the meson spectrum is discrete and possesses a mass gap. As the temperature increases, the branes approach a critical solution. Eventually, they fall into the horizon and a phase trans...

We present evidence for a novel finite-temperature phase transition in the phason elasticity of quasicrystals. A tiling model for energetically stabilized decagonal quasicrystals has been studied in an extensive series of Monte Carlo simulation. Hamiltonian (energetics) of the model is given by nearestneighbor Penrose-like matching rules between three dimensional unit cells. A new order paramet...