Related papers: Element-specific ultrafast lattice dynamics in mon…
High-energy optical transitions in monolayer transition-metal dichalcogenides exhibit characteristics that are markedly distinct from those of lower-lying band-edge excitons. These differences arise from the involvement of electronic states…
Disentangling the primary order parameter from secondary order parameters in phase transitions is critical to the interpretation of the transition mechanisms in strongly correlated systems and quantum materials. Here we present a study of…
We report on the dynamics of coherent phonons in semimetal 1T'-MoTe2 using femtosecond pump-probe spectroscopy. On an ultrafast sub-picosecond time scale at room temperature, a low frequency and long-lifetime shear phonon mode was observed…
Ultrafast diffraction is the cutting-edge technique to extract the atomic temperature at femtosecond timescales, and further related quantities - in particular, electron-phonon coupling strength at elevated electronic temperatures. The…
Using a microscopic dipole lattice model including electronic polarization (EP) of ions and local field effects (LFEs) self-consistently, two sets of three equations are deduced for long wavelength in-plane and out-of-plane optical lattice…
The transition between different states in manganites can be driven by various external stimuli. Controlling these transitions with light opens the possibility to investigate the microscopic path through which they evolve. We performed…
Wigner crystals, lattices made purely of electrons, are a quintessential paradigm of studying correlation-driven quantum phase transitions. Despite decades of research, the internal dynamics of Wigner crystals has remained extremely…
Transition metal dichalcogenide monolayers and heterostructures are highly tunable material systems that provide excellent models for physical phenomena at the two-dimensional (2D) limit. While most studies to date have focused on electrons…
In the prevalent picture of ultrafast structural phase transitions, the atomic motion occurs in a slowly varying potential energy surface determined adiabatically by the fast electrons. However, this ignores non-conservative forces caused…
Here we show how time-resolved broadband optical spectroscopy can be used to quantify, with femtometer resolution, the oscillation amplitudes of coherent phonons through a displacive model without free tuning parameters, except an overall…
We investigate the ultrafast dynamics of photo-induced non-thermal lattice disorder in a polycrystalline aluminium thin film to elucidate transient short- and long-range lattice distortions, their thermalization and electron-phonon coupling…
We use a coherent Bragg diffraction method to impart an external momentum to ultracold bosonic atoms trapped in a one-dimensional optical lattice. This method is based on the application of a single light pulse, with conditions where…
Metals exhibit nonequilibrium electron and lattice subsystems at transient times following femtosecond laser excitation. In the past four decades, various optical spectroscopy and time-resolved diffraction methods have been used to study…
Femtosecond time-resolved core-level photoemission spectroscopy with a free-electron laser is used to measure the atomic-site specific charge-order dynamics in the charge-density-wave/Mott insulator 1T-TaS2. After strong photoexcitation, a…
The spectral and spatiotemporal dynamics of photoluminescence in monolayers of transition metal dichalcogenide WSe$_2$ obtained by mechanical exfoliation on a Si/SiO$_2$ substrate is studied over a wide range of temperatures and excitation…
In condensed matter, scattering processes determine the transport of charge carriers. In case of heterostructures, interfaces determine many dynamic properties like charge transfer and transport and spin current dynamics. Here we discuss…
Melting is an everyday phase transition that is determined by thermodynamic parameters like temperature and pressure. In contrast, ultrafast melting is governed by the microscopic response to a rapid energy input and, thus, can reveal the…
Identifying and understanding the mechanisms behind strong phonon-phonon scattering in condensed matter systems is critical to maximizing the efficiency of thermoelectric devices. To date, the leading method to address this has been to…
Time-resolved elastic neutron scattering combined with rapid laser heating was used to probe the charge density wave (CDW) state in 1T-TiSe$_2$, capturing both the melting and reformation of the CDW on long timescales and providing clues on…
We combine femtosecond electron diffuse scattering experiments and first-principles calculations of the coupled electron-phonon dynamics to provide a detailed momentum-resolved picture of the ultrafast lattice thermalization in a thin film…