Large acoustic transients induced by nonthermal melting of InSb.
نویسندگان
چکیده
We have observed large-amplitude strain waves following a rapid change in density of InSb due to nonthermal melting. The strain has been measured in real time via time-resolved x-ray diffraction, with a temporal resolution better than 2 ps. The change from the solid to liquid density of the surface layer launches a high-amplitude strain wave into the crystalline material below. This induces an effective plane rotation in the asymmetrically cut crystal leading to deflection of the diffracted beam. The uniform strain in the layer below the molten layer is 2.0(+/-0.2)%. A strain of this magnitude develops within 5 ps of the incident pulse showing that the liquid has reached the equilibrium density within this time frame. Both the strain amplitude and the depth of the strained material in the solid can be explained by assuming a reduction in the speed of sound in the nonequilibrium liquid compared to measured equilibrium values.
منابع مشابه
Femtosecond x-ray measurement of ultrafast melting and large acoustic transients.
Time-resolved x-ray diffraction with ultrashort ( approximately 300 fs), multi-keV x-ray pulses has been used to study the femtosecond laser-induced solid-to-liquid phase transition in a thin crystalline layer of germanium. Nonthermal melting is observed to take place within 300-500 fs. Following ultrafast melting we observe strong acoustic perturbations evolving on a picosecond time scale.
متن کاملObservation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb.
The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotro...
متن کاملSignatures of nonthermal melting
Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing no...
متن کاملPhase transformations of an InSb surface induced by strong femtosecond laser pulses.
Phase transformations of InSb~211! induced by 130-fs laser pulses at 800 nm have been time resolved in a wide range of laser fluences. The pump-probe technique has been used, where both optical reflectivity and reflected second-harmonic generation ~SHG! from the probe pulses are monitored as functions of probe versus pump pulse delay. The results are indicative of InSb undergoing a phase transi...
متن کاملQuantum Hooke's Law to Classify Pulse Laser Induced Ultrafast Melting
Ultrafast crystal-to-liquid phase transition induced by femtosecond pulse laser excitation is an interesting material's behavior manifesting the complexity of light-matter interaction. There exist two types of such phase transitions: one occurs at a time scale shorter than a picosecond via a nonthermal process mediated by electron-hole plasma formation; the other at a longer time scale via a th...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physical review letters
دوره 98 22 شماره
صفحات -
تاریخ انتشار 2007