Related papers: Photoinduced multistage phase transitions in Ta2Ni…
The dynamics of the photoinduced commensurate to incommensurate charge density wave (CDW) phase transition in 4Hb-TaSe2 are investigated by femtosecond electron diffraction. In the perturbative regime the CDW reforms on a 150 ps timescale,…
Characterizing and controlling the out-of-equilibrium state of nanostructured Mott insulators hold great promises for emerging quantum technologies while providing an exciting playground for investigating fundamental physics of…
The photoinduced valence dynamics of EuNi$_2$(Si$_{0.21}$Ge$_{0.79}$)$_2$ are investigated using time-resolved X-ray absorption spectroscopy for Eu $M_5$-edge. Through the pump-probe technique with synchrotron X-ray and Ti:sapphire laser…
Quantum materials represent one of the most promising frontiers in the quest for faster, lightweight, energy efficient technologies. However, their inherent complexity and rich phase landscape make them challenging to understand or…
Photo-induced phase transitions (PIPTs) provide an ultrafast, energy-efficient way for precisely manipulating the topological properties of transition-metal ditellurides, and can be used to stabilize a topological phase in an otherwise…
Topological materials are of great interest because they can support metallic edge or surface states that are robust against perturbations, with the potential for technological applications. Here we experimentally explore the light-induced…
The layered chalcogenide Ta2NiSe5 has recently attracted much interest as a strong candidate for the long sought excitonic insulator (EI). Since the physical properties of an EI are expected to depend sensitively on the external pressure,…
Using time- and angle-resolved photoemission, we investigate the ultrafast response of excited electrons in the ternary topological insulator (Bi$_{1 x}$Sb$_{x}$)$_2$Te$_3$ to fs-infrared pulses. We demonstrate that at the critical…
Coulomb attraction between electrons and holes in a narrow-gap semiconductor or a semimetal is predicted to lead to an elusive phase of matter dubbed 'excitonic insulator'. However, direct observation of such electronic instability remains…
The transient optical conductivity of photoexcited 1T-TaS2 is determined over a three-order-of-magnitude frequency range. Prompt collapse and recovery of the Mott gap is observed. However, we find important differences between this…
Ta$_{3}$N$_{5}$ is among the most intensively studied photoanode materials for solar-driven water oxidation, yet its performance often remains limited by short carrier lifetimes and defect mediated recombination. Although transient…
We use optical-pump terahertz-probe spectroscopy to investigate the near-threshold behavior of the photoinduced insulator-to-metal (IM) transition in vanadium dioxide thin films. Upon approaching Tc a reduction in the fluence required to…
Polymorphic transitions in layered transition metal dichalcogenides provide an excellent platform for discovering exotic phenomena associated with metastable states, ranging from topological phase transitions to enhanced superconductivity.…
From thermodynamic analysis we demonstrate that during metal-insulator transitions in pure matters, a nonequilibrium homogeneous state may be unstable against charge density modulations with certain wavelengths, and thus evolves to the…
We use time-resolved hard x-ray diffraction to investigate the structural dynamics of the multiferroic insulator TbMnO$_3$ in the low temperature antiferromagnetic and ferroelectrically ordered phase. The lattice response following…
We study the photo-induced metallization process in niobium dioxide NbO$_2$. This compound undergoes the thermal insulator-to-metal transition at the remarkably high temperature of 1080 K. Our optical pump - terahertz probe measurements…
Here we report extensive ultrafast time-resolved reflectivity experiments on overdoped Bi$_{2}$Sr$_{2}$Ca$_{1-x}$Y$_x$Cu$_{2}$O$_{8+\delta}$ single crystals (T$_C$=78 K) aimed to clarify the nature of the superconducting-to-normal-state…
The complex interplay between several active degrees of freedom (charge, lattice, orbtial and spin order) is thought to determine the electronic properties of many oxides, but the respective role of the various contributions is often…
Photoinduced non-thermal phase transitions are new paradigms of exotic non-equilibrium physics of strongly correlated materials. An ultrashort optical pulse can drive the system to a new order through complex microscopic interactions that…
We apply ultrafast spectroscopy to establish a time-domain hierarchy between structural and electronic effects in a strongly-correlated electron system. We discuss the case of the model system VO2, a prototypical non-magnetic compound that…