Ultrafast quasiparticle dynamics of FeTe0.75Se0.25superconductor

1 Nonlinear Terahertz Studies of Ultrafast Quasiparticle Dynamics in Semiconductors

Anisotropy of Quasiparticle Lifetimes and the Role of Disorder for Ultrafast Electron Dynamics in Graphite

Femtosecond time-resolved photoemission of photoexcited electrons in highly oriented pyrolytic graphite (HOPG) provides strong evidence for anisotropies of quasiparticle (QP) lifetimes. Indicative of such anisotropies is a pronounced anomaly in the energy dependence of QP lifetimes between 1.1 eV and 1.5 eV – the vicinity of a saddle point in the graphite bandstructure. This is supported by rec...

Ultrafast quasiparticle relaxation dynamics in normal metals and heavy-fermion materials

We present a detailed theoretical study of the ultrafast quasiparticle relaxation dynamics observed in normal metals and heavy-fermion materials with femtosecond time-resolved optical pump-probe spectroscopy. For normal metals, a nonthermal electron distribution gives rise to a temperature~T! independent electron-phonon relaxation time at low temperatures, in contrast to the T-divergent behavio...

Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy

A hallmark in the cuprate family of high-temperature superconductors is the nodal-antinodal dichotomy. In this regard, angle-resolved photoemission spectroscopy (ARPES) has proven especially powerful, providing band structure information directly in energy-momentum space. Time-resolved ARPES (trARPES) holds great promise of adding ultrafast temporal information, in an attempt to identify differ...

Ultrafast Reaction Dynamics

With new laser techniques and with gas phase and molecular beam experiments, it is now possible to determine the ultrafast motion in isolated chemical reactions-chemistry on the I 0 l 3 -second time scale. A decade ago this magazine devoted a special issue to laser chemistry (see PHYSICS TODAY, November 1980). One of the articles emphasized the importance of time scales in chemical reactions an...