Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 30: Poster 2
HL 30.43: Poster
Thursday, September 8, 2022, 11:00–13:00, P3
Pulse-driven non-adiabatic tunneling in nanocontacts: quasiclassical approach — Sangwon Kim1, Tobias Schmude2, Guido Burkard2, and •Andrey S. Moskalenko1 — 1KAIST, Daejeon, Korea — 2University of Konstanz, Konstanz, Germany
We develop a general quasiclassical theory for the description of the tunneling through time-dependent barriers induced by ultrashort light pulses and apply it to the tunneling induced by such pulses in nanocontacts [1]. In particular, we analyze the situation when the tunneling is driven by ideal half-cycle pulses. Among the numerous solutions that contribute to the tunneling probability, we choose two main solution branches with the largest contributions: The 1st solution exhibits the "tunneling" behavior of a wave packet whereas the 2nd solution exhibits the "evanescent-wave" behavior. For a large enough intercontact distance, the 1st solution dominates in terms of the tunneling probability. However, for minute distances and small field strengths, when the electron does not manage to escape from the classically forbidden region, the 2nd solution starts to dominate. Finally, we study a situation when the tunneling is driven by realistic few-cycle pulses. We see that the direction of the electron transport in the nanocontacts may be altered in dependence on the carrier-envelope phase of the driving pulse. We also find that the time when the electron effectively emerges from under the barrier does not necessarily exactly coincide with one of the peaks of the driving electric field.
[1] Sangwon Kim et al., New J. Phys. 23, 083006 (2021).