Tunneling of a Wave Packet
Abstract
Analytic expressions are given for the time spent by a particle tunneling through a potential barrier. The expressions are derived for an incident wave packet which is initially Gaussian, centered about a point an arbitrary distance away from a rectangular potential barrier and moving toward the barrier with constant average velocity. Upon collision with the barrier, the packet splits into a transmitted and a reflected packet. The resultant transmission time is positive, nonzero and in principle measurable. Although the transmission time becomes quite large as the incident kinetic energy becomes very small, in general, for nonzero incident momentum and finite potential barriers which are neither very thick nor very thin, the transmission times are less than the time that would be required for the incident particle to travel a distance equal to the barrier thickness. The transmission times for metalinsulatormetal thin film sandwiches, given approximately by δt_{3}=ℏ/(E_{f}φ)^{1/2}, where E_{f} is the Fermi energy of the metal, and φ the vacuum work function, are of the order of 10^{16} sec, compared to RC time constants of about 10^{13} sec.
 Publication:

Journal of Applied Physics
 Pub Date:
 December 1962
 DOI:
 10.1063/1.1702424
 Bibcode:
 1962JAP....33.3427H