Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

985
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
985
Spin–Spin Coupling: One-Bond Coupling01:17

Spin–Spin Coupling: One-Bond Coupling

951
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
951
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K
¹H NMR: Long-Range Coupling01:27

¹H NMR: Long-Range Coupling

1.7K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
1.7K
Spin–Spin Coupling Constant: Overview01:08

Spin–Spin Coupling Constant: Overview

900
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
900
NMR Spectroscopy: Spin–Spin Coupling01:08

NMR Spectroscopy: Spin–Spin Coupling

1.3K
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved...
1.3K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Probing Moiré Excitons in MoSe<sub>2</sub>/WSe<sub>2</sub> Heterobilayers by Combined Micro-photoluminescence and Lateral Force Microscopy.

Nano letters·2026
Same author

Imaging the flat bands of magic-angle graphene reshaped by interactions.

Nature·2026
Same author

Revealing Electron-Electron Interactions in Graphene at Room Temperature with a Quantum Twisting Microscope.

Nano letters·2026
Same author

Thermopower Probe of Fractional Quantum Hall States in Monolayer Graphene.

Physical review letters·2026
Same author

Optical control over topological Chern number in moiré materials.

Nature·2026
Same author

Observation of a superfluid-to-insulator transition of bilayer excitons.

Nature·2026

Related Experiment Video

Updated: Jun 18, 2025

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials
10:36

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Published on: January 21, 2016

10.6K

Strongly coupled edge states in a graphene quantum Hall interferometer.

Thomas Werkmeister1, James R Ehrets2, Yuval Ronen2,3

  • 1John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.

Nature Communications
|August 2, 2024
PubMed
Summary

Quantum Hall effect interferometers reveal how electron interactions cause apparent particle pairing. Tuning electron density in graphene clarifies the link between phase jumps and Aharonov-Bohm frequency doubling in edge channels.

More Related Videos

Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
05:39

Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform

Published on: August 2, 2019

9.6K
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
11:42

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities

Published on: July 24, 2015

15.4K

Related Experiment Videos

Last Updated: Jun 18, 2025

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials
10:36

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Published on: January 21, 2016

10.6K
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
05:39

Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform

Published on: August 2, 2019

9.6K
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
11:42

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities

Published on: July 24, 2015

15.4K

Area of Science:

  • Condensed Matter Physics
  • Quantum Mechanics
  • Materials Science

Background:

  • Quantum Hall effect (QHE) edge channels enable studies of fundamental physics.
  • Fabry-Pérot (FP) interferometers in QHE systems reveal quasiparticle statistics and anomalous phenomena.
  • Aharonov-Bohm (AB) interference frequency doubling suggests electron pairing into exotic quasiparticles.

Purpose of the Study:

  • To investigate the connection between interference phase jumps and AB frequency doubling in QHE FP interferometers.
  • To elucidate the role of electron-electron interactions in observed pairing phenomena.
  • To utilize a tunable graphene-based QHE FP interferometer for in-situ interaction studies.

Main Methods:

  • Fabrication and operation of a tunable graphene-based quantum Hall effect Fabry-Pérot interferometer.
  • In-situ tuning of electron density across various filling factors ( to ).
  • Measurement and analysis of interference phase jumps and Aharonov-Bohm oscillations.

Main Results:

  • Observed periodic interference phase jumps correlating with Aharonov-Bohm frequency doubling.
  • Demonstrated that repulsive interactions between spin-split edge channels drive the apparent pairing.
  • Showcased the effect of charge screening between localized and extended edge channels.

Conclusions:

  • Repulsive interactions and charge quantization in edge channels explain AB frequency doubling.
  • Graphene QHE interferometers are sensitive probes of microscopic interactions in one-dimensional systems.
  • Enables future research on correlated electrons in 1D channels using tunable graphene devices.