相关论文: Dynamic Simulation of Structural Phase Transitions…
We use first-principles techniques to re-examine the suggestion that transitions seen in high-P experiments on Mo are solid-solid transitions from the bcc structure to either the fcc or hcp structures. We confirm that in the harmonic…
Response of pure Ising systems to time-dependent external magnetic fields, like pulsed and oscillating fields, are discussed and compared here. Because of the two time scales involved, namely the thermodynamic relaxation time of the system…
We present a method for the direct evaluation of the difference between the free energies of two crystalline structures, of different symmetry. The method rests on a Monte Carlo procedure which allows one to sample along a path, through…
We study in this paper the phase transition in superlattices formed by alternate magnetic and ferroelectric layers, by the use of Monte Carlo simulation. We study effects of temperature, external magnetic and electric fields,…
The structure and stability of iron near melting at multi-megabar pressures are of significant interest in high pressure physics and earth and planetary sciences. While the body-centered cubic (BCC) phase is generally recognized as unstable…
Within the harmonic approximation, the effects of lattice vibration on the thermodynamics of nano-sized coherent clusters in bcc-Fe consisting of vacancies and/or copper are investigated. A combination of on-lattice simulated annealing…
We investigate the superfluid phase transition in a gas of Fermi atoms loaded on a three-dimensional optical lattice. When the lattice potential is strong, this system can be well described by an attractive Hubbard model. In this model, we…
Driven non-equilibrium structural phase transformation has been probed using time varying resistance fluctuations or noise. We demonstrate that the non-Gaussian component (NGC) of noise obtained by evaluating the higher order statistics of…
The evaluation of phase stabilities of unstable elemental phases is a long-standing problem in the computational assessment of phase diagrams. Here we tackle this problem by explicitly calculating phase diagrams of intermetallic systems…
The nature of the elemental cerium phases, undergoing an isostructural volume collapse transition, cannot be understood using conventional solid state concepts. Using the combination of density functional theory and dynamical mean-field…
We apply the phase field crystal model to study the structure and energy of symmetric tilt grain boundaries of bcc iron in 3D. The parameters for the model are obtained by using a recently developed eight-order fitting scheme [A. Jaatinen…
We present calculations of free energy barriers and diffusivities as functions of temperature for the diffusion of hydrogen in bcc-Fe. This is a fully quantum mechanical approach since the total energy landscape is computed using a new self…
We review our studies of elastic lattices driven by an external force $F$ in the presence of random disorder, which correspond to the case of vortices in superconducting thin films driven by external currents. Above a critical force $F_c$…
The metal-insulator transition (MIT) in rare-earth nickelates exemplifies the intricate interplay between electronic correlations and lattice dynamics in quantum materials. This work focuses on SmNiO$_3$ as a prototypical system, employing…
We discuss the role of dynamical many-electron effects in the physics of iron and iron-rich solid alloys under applied pressure on the basis of recent ab initio studies employing the dynamical mean-field theory (DMFT). Electronic…
The phase diagram of the iron arsenides is dominated by a magnetic and a structural phase transition, which need to be suppressed in order for superconductivity to appear. The proximity between the two transition temperature lines indicates…
We investigate the charge and lattice states in a quasi-one-dimensional organic ferroelectric material, TTF-QCl$_{4}$, under pressures of up to 35 kbar by nuclear quadrupole resonance experiments. The results reveal a global…
Investigation of magnetic materials at realistic conditions with first-principles methods is a challenging task due to the interplay of vibrational and magnetic degrees of freedom. The most difficult contribution to include in simulations…
We report neutron diffraction studies of low density bcc and hcp solid 4He. In the bcc phase, we observed a continuous dynamical behaviour involving macroscopic structural changes of the solid. The dynamical behaviour takes place in a cell…
Motivated by recent experimental observations [Phys. Rev. 96, 020407 (2017)] on hexagonal ferrites, we revisit the phase diagrams of diluted magnets close to the lattice percolation threshold. We perform large-scale Monte Carlo simulations…