ISSN:
1432-0630
Keywords:
PACS: 61.80.Ba; 63.20.
;
e; 78.47.+p
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract. We analyze the femtosecond instability of the diamond lattice of silicon and GaAs, which is induced by a dense electron–hole plasma after excitation by a very intense laser pulse. We obtain that the electron–hole plasma causes an instability of both transverse acoustic and longitudinal optical phonons. So, within less than 200 fs, the atoms are displaced more than 1 A˚ from their equilibrium position. The gap between the conduction and the valence band then vanishes and the symmetries of the diamond structure are destroyed, which has important effects on the optical reflectivity and second-harmonic generation. After that, the crystal melts very rapidly because of the high kinetic energy of the atoms. Note that this is in good agreement with recent experiments done on Si and GaAs using a pump laser to excite a dense electron–hole plasma and a probe laser to observe the resulting changes in the atomic and electronic str ucture.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003390050089
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