Related papers: Ultrafast lattice disordering can be accelerated b…
We present a constrained density functional perturbation theory scheme for the calculation of structural and harmonic vibrational properties of insulators in the presence of an excited and thermalized electron-hole plasma. The method is…
1T'-TaTe2 exhibits an intriguing first-order structural phase transition at around 170 K. Understanding the electronic structural properties is a crucial way to comprehend the origin of the structural phase transition. We performed a…
Phase transitions are ubiquitous, appearing at every length scale from atoms to galaxies. In condensed matter, ultrafast laser pulses drive materials to highly non-equilibrium conditions allowing transitions to new phases of matter not…
We study the nonequilibrium dynamics of photoinduced phase transitions in charge ordered (CO) systems with a strong electron-lattice interaction and analyze the interplay between electrons, periodic lattice distortions, and a phonon thermal…
Using the Boltzmann transport equation (BTE), we study the evolution of nonequilibrium carrier distributions in simple ($sp$) metals, assumed to have been instantaneously excited by an ultrafast laser pulse with photon energy $h \nu$. The…
Mechanical metamaterials can be designed to exhibit unique mechanical properties, including tunable auxetic behavior as well as multi-stability, which arise from the geometry and configuration of the constituent building blocks.…
We report studies on the vibrational and elastic behavior of lithium oxide, Li2O around its superionic transition temperature. Phonon frequencies calculated using the ab-initio and empirical potential model are in excellent agreement with…
We analyze in detail the heating of bosonic atoms in an optical lattice due to incoherent scattering of light from the lasers forming the lattice. Because atoms scattered into higher bands do not thermalize on the timescale of typical…
Using light to control transient phases in quantum materials is an emerging route to engineer new properties and functionality, with both thermal and non-thermal phases observed out of equilibrium. Transient phases are expected to be…
Diffusion of heat in metals is a fundamental process which is crucial for a variety of applications of metal nanostructures. Surprisingly, however, {\em ultrafast} heat diffusion received only limited attention so far. Here, we show that…
While the vibrational thermodynamics of materials with small anharmonicity at low temperatures has been understood well based on the harmonic phonons approximation; at high temperatures, this understanding must accommodate how phonons…
Ultrafast optical pump - optical probe and optical pump - terahertz probe spectroscopy were performed on vanadium dioxide (VO2) and vanadium sesquioxide (V2O3) thin films over a wide temperature range. A comparison of the experimental data…
The ultrafast time-dependence of the energy absorption of covalent solids upon excitation with femtosecond laser pulses is theoretically analyzed. We use a microscopic theory to describe laser induced structural changes and their influence…
We present a theoretical study of the ultrafast electron dynamics in transition metals using ultrashort pulsed laser beams. The significant influence of the contribution of the dynamics of produced nonthermal electrons to electron…
In this experiment a steady state current is maintained through a liquid crystal thin film. When the applied voltage is increased through a threshold, a phase transition is observed into a convective state characterized by the chaotic…
Order-disorder transitions take place in many physical systems, but observing them in detail in real materials is difficult. In two- or quasi-two-dimensional systems, the transition has been studied by computer simulations and…
Realistic simulations of current ultra-cold atoms experiments in optical lattices show that the ramping up of the optical lattice is significantly nonadiabatic, implying that experimentally prepared Mott insulators are not really in the…
Femtosecond laser excitation of solid-state systems creates non-equilibrium hot electrons that cool down by transferring their energy to other degrees of freedom and ultimately to lattice vibrations of the solid. By combining ab initio…
Utilizing ultrafast light-matter interaction to manipulate electronic states of quantum materials is an emerging area of research in condensed matter physics. It has significant implications for the development of future ultrafast…
We demonstrate that in confined plasmonic metal structures subject to ultra-fast laser excitation electron thermal diffusion can provide relaxation faster than the energy transfer to the lattice. This relaxation occurs due to excitation of…