Related Experiment Video
Updated: Jun 21, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Pseudospin valve in bilayer graphene: towards graphene-based pseudospintronics
P San-Jose1, E Prada, E McCann
1Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom.
Physical Review Letters
|August 8, 2009
Summary
We introduce a novel nonmagnetic pseudospin valve using graphene bilayers, controlled by external gates. This device shows a large on-off ratio, paving the way for pseudospintronics applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Spintronics utilizes electron spin for information processing.
- Existing spintronic devices often rely on magnetic materials.
- Graphene's unique electronic properties offer potential for novel electronic functionalities.
Purpose of the Study:
- To propose and theoretically investigate a nonmagnetic pseudospin valve based on graphene bilayers.
- To explore the feasibility of controlling pseudospin polarization using external electric fields.
- To assess the potential of this device for future electronic applications.
Main Methods:
- Theoretical modeling of pseudospin polarization in gated graphene bilayers.
- Numerical calculations to simulate device characteristics.
- Analysis of the on-off ratio based on pseudospin manipulation.
Main Results:
- Demonstration of a nonmagnetic spin valve functionality using pseudospin in graphene.
- Achieved a large on-off ratio through gate-controlled pseudospin polarization.
- Validation of the device concept via numerical simulations.
Conclusions:
- The proposed pseudospin valve is a viable nonmagnetic alternative to traditional spin valves.
- Gate-controlled pseudospin manipulation in graphene is effective for device operation.
- This work lays the foundation for the emerging field of pseudospintronics.
Related Concept Videos
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
01:17Spin–Spin Coupling: One-Bond Coupling
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,...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
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...
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...
01:08Spin–Spin Coupling Constant: Overview
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 have a...
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 have a...
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
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 involved orbitals. The...
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 involved orbitals. The...
03:06The Pauli Exclusion Principle
The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that contains three pieces of information: