Related Experiment Video
Updated: Feb 2, 2026
10:28
Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
9.5K
Tunneling time probed by quantum shot noise.
Pierre Février1, Julien Gabelli2
1Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France.
Nature Communications
|November 24, 2018
Summary
We directly measured tunneling traversal time in metallic junctions by detecting infrared photon emission, which arises from current fluctuations. This optical method probes electron transport dynamics at femtosecond timescales.
Area of Science:
- Condensed Matter Physics
- Quantum Transport
- Nanophysics
Background:
- Electron tunneling in metallic junctions occurs on femtosecond timescales.
- Measuring this ultrafast tunneling time is experimentally challenging.
- Junctions emit infrared radiation above 1V bias, acting as optical antennas.
Purpose of the Study:
- To develop a method for directly measuring electron tunneling traversal time.
- To investigate the relationship between photon emission and current fluctuations.
- To probe quantum transport dynamics in far-from-equilibrium conditions.
Main Methods:
- Performed optical spectroscopy and electronic current fluctuation measurements.
- Utilized infrared photon emission from metallic tunnel junctions as a probe.
- Analyzed data within the Landauer-Büttiker scattering formalism.
Main Results:
- Demonstrated that photon emission originates from current fluctuations within the tunneling barrier.
- Showed photon detection is equivalent to measuring high-frequency current fluctuations.
- Achieved direct estimation of the electron traversal time.
Conclusions:
- Photon emission provides a direct optical probe for ultrafast electron transport.
- Combines optical and electronic measurements to characterize tunneling dynamics.
- Validates theoretical predictions for quantum transport in metallic junctions.
Related Concept Videos
02:43Quantum Numbers
50.1K
It is said that the energy of an electron in an atom is quantized; that is, it can be equal only to certain specific values and can jump from one energy level to another but not transition smoothly or stay between these levels.
50.1K
02:45The Quantum-Mechanical Model of an Atom
57.3K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
57.3K
03:31Labeling DNA Probes
9.4K
DNA probes are fragments of DNA labeled with a reporter tag to enable their detection or purification. The resulting labeled DNA probes can then hybridize to target nucleic acid sequences through complementary base-pairing, and may be used to recover or identify these regions.
Radioisotopes, fluorophores, or small molecule binding partners like biotin or digoxigenin, are the most widely used reporter tags for labeling DNA probes. These labels can be attached to the probe DNA molecule via...
Radioisotopes, fluorophores, or small molecule binding partners like biotin or digoxigenin, are the most widely used reporter tags for labeling DNA probes. These labels can be attached to the probe DNA molecule via...
9.4K
01:192D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
1.4K
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...
1.4K
01:22Mean free path and Mean free time
5.1K
Consider the gas molecules in a cylinder. They move in a random motion as they collide with each other and change speed and direction. The average of all the path lengths between collisions is known as the "mean free path."
5.1K
01:19Mixing Time
483
The concept of mixing time is significant in producing a uniform concrete mix with the required strength. The mixing period starts once all components are in the mixer. Initially, the mixer is charged with 10% of the water, followed by the consistent addition of solids and then 80% of the water. The remaining water is added later, within the first quarter of the mixing period. The minimum mixing time varies according to the mixer's capacity; for example, mixers with up to 1 cubic yard...
483