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South Korean researchers from Pohang University of Science and Technology (POSTECH) for the first time reveal the process of «of electron tunneling», which has been a concern of scientists around the world for more than 100 years.
«Thanks to this study, we were able to get an idea of how electrons behave when passing through the atomic wall», — explains Professor from the Department of Physics at POSTECH Dong Yong Kim.
Researchers have found that the idea of walking through walls looks like a science fiction movie, but similar phenomena really happen in the atomic world. «Quantum tunneling» refers to the passage of electrons through energy barriers that they cannot overcome with their own energy. In this way, the particles seem to tunnel through these barriers.
During the experiment, the scientists used high-intensity laser beams to cause the effect of electron tunneling in atoms. It turned out that the electrons not only pass through the energy barriers, but also collide with the atomic nucleus again inside the tunnel. Until now, it was believed that electrons were able to interact with the nucleus only after leaving the tunnel. However, a new study has confirmed that the interaction can also occur inside the tunnel.
The study reveals the dynamics of sub-barrier resonances leading to Freeman resonances. The model of sub-barrier resonances, which goes beyond the description of direct multiphoton transitions, predicts the features of Freeman resonances that cannot be explained within the existing scenario of direct multiphoton transitions.
«The model predicts the dominance of high-order Freeman resonances over ionization, above a threshold in the energy spectra of photoelectrons, and a flat dependence of the Freeman resonance signal on laser intensity, as in the non-adiabatic tunneling mode», — the researchers emphasize.
In the experiments, electrons accumulated energy inside the barrier and collided with the nucleus again, enhancing the so-called «Freeman resonance». This ionization is significantly higher than that observed in previously known ionization processes and is practically independent of changes in laser intensity.
This discovery was not predicted by existing theories. According to the researchers, the results of the experiments will lay an important scientific basis for more precise control of electron behavior, which will allow increase efficiency semiconductor devices, quantum computers, and ultrafast lasers.
The results of the study were published in Physics Review Letters
Source: Interesting Engineering