NUMERICAL-STUDIES OF TUNNELING IN A NONHARMONIC TIME-DEPENDENT POTENTIAL

Citation
Ja. Stovneng et Ap. Jauho, NUMERICAL-STUDIES OF TUNNELING IN A NONHARMONIC TIME-DEPENDENT POTENTIAL, Physical review. B, Condensed matter, 47(16), 1993, pp. 10446-10451
Citations number
19
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
47
Issue
16
Year of publication
1993
Pages
10446 - 10451
Database
ISI
SICI code
0163-1829(1993)47:16<10446:NOTIAN>2.0.ZU;2-3
Abstract
Tunneling through time-dependent potentials is of relevance to a numbe r of physical problems. Using a WKB analysis, Azbel' has recently stud ied the effects of a nonharmonic time-dependent perturbation embedded in an opaque potential barrier. He suggests the existence of three dif ferent regimes for transmission in such systems: direct tunneling, act ivation-assisted tunneling, and elevator resonant activation. We addre ss the same problem with a numerical technique based on wave-packet si mulations. Our numerical results are in qualitative agreement with the picture of Azbel'. The outcome depends on the characteristic time T o f the nonharmonic potential. There is a transition from direct tunneli ng to the activation regime around a ''crossover'' value T(c) which is determined by the Buttiker-Landauer time, the distance between the in itial energy and the lowest resonant level, and the amplitude of the t ime-dependent perturbation. The total transmission probability is stro ngly enhanced when entering the activation regime.