J1-4022 — Annual report 2011
1.
Anharmonic order-parameter oscillations and lattice coupling in strongly driven 1 T-TaS[sub]2 and TbTe[sub]3 charge-density-wave compounds

By analyzing the observed phenomena in the framework of time-dependent Ginzburg-Landau theory authors attributed the effects to the anharmonicity of the mode potentials inherent to the broken symmetry state of the CDW systems.

COBISS.SI-ID: 24372007
2.
Mechanisms of nonthermal destruction of the superconducting state and melting of the charge-density-wave state by femtosecond laser pulses

The processes leading to nonthermal condensate vaporization and charge-density-wave (CDW) melting with femtosecond laser pulses is systematically investigated in different materials. We find that vaporization is relatively slow (τv∼1 ps) and inefficient in superconductors, exhibiting a strong systematic dependence of the vaporization energy Uv on Tc. In contrast, melting of CDW order proceeds rapidly (τm=50–200 fs) and more efficiently. A quantitative model describing the observed systematic behavior in superconductors is proposed based on a phonon-mediated quasiparticle (QP) bottleneck mechanism. In contrast, Fermi-surface disruption by hot QPs is proposed to be responsible for CDW state melting.

COBISS.SI-ID: 25274151
3.
Ultrafast phase separation dynamics in La[sub](0.875)Sr[sub](0.125)MnO[sub]3 single crystals

The transient photoinduced reflectivity and the transient photoinduced magnetooptical Kerr angle were measured in a La0.875Sr0.125MnO3 single crystal as functions of temperature. A separate photoinduced transient ferromagnetic phase is found to form within the pseudocubic low-temperature insulating ferromagnetic phase after photoexcitation. The characteristic time of transient phase formation is on the order of 10 ps. The similarity with Pr0.6Ca0.4MnO3 indicates that the photoinduced transient ferromagnetic phase is a general property of the insulating ferromagnetic state in colossal-magnetoresistive manganites.

COBISS.SI-ID: 24566055