We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Dynamics of a Peierls system in a light field.
- Authors
Semenov, A. L.
- Abstract
Equations describing the temporal dynamics of the order parameter Ξ(t) of a metal-semiconductor phase transition and the density n(t) of electron-hole pairs in a Peierls system in a light field are obtained on the basis of the Lagrange equation for the phonon mode and the Liouville equation for the density matrix of the electronic subsystem. The equations obtained are analyzed for a stationary state (with adiabatically slow variation of the light intensity I) and for a transient process near the initial and final states of dynamic equilibrium (with the light field switched on abruptly). It is shown that for adiabatically slow growth of the intensity I up to a certain critical value I[sub c] the band gap of the electronic spectrum decreases but the semiconductor phase of the Peierls system remains stable. For I>I[sub c] the stationary semiconductor state (Ξ≠0) becomes unstable. When the light is switched on abruptly, the deviation of the system parameters from the initial values is described by an exponential law with a characteristic reciprocal of the rise time of the process linearly dependent on the irradiation intensity I. As a new position of equilibrium is approached, three qualitatively different regimes of behavior of the order parameter Ξ and density n are possible. For low intensities I (I<I[sub 1]) a purely relaxational aperiodic process occurs. For intermediate intensities I (I[sub 1]<I<I[sub c]) damped oscillations of Ξ and n are observed near a new stationary semiconductor state with a smaller band gap. For I>I[sub c] the stationary semiconductor state with Ξ≠0 is absent. The experimental data on the irradiation of a vanadium dioxide film with a powerful laser pulse is interpreted on the basis of the theory developed.
- Subjects
PHASE transitions; STATISTICAL physics
- Publication
Journal of Experimental & Theoretical Physics, 1999, Vol 89, Issue 6, p1168
- ISSN
1063-7761
- Publication type
Article
- DOI
10.1134/1.559068