Related Experiment Video
Updated: May 14, 2026
15:47
Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
Two- and three-electron Pauli spin blockade in series-coupled triple quantum dots
1RIKEN Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. s-amaha@riken.jp
Physical Review Letters
|February 7, 2013
Summary
We studied spin blockade in quantum dots (QDs). Spin blockade occurs when electron tunneling is restricted, requiring specific conditions for triplet and quadruplet states, crucial for quantum information processing.
Area of Science:
- Quantum physics
- Condensed matter physics
- Nanotechnology
Background:
- Spin blockade is a key phenomenon in quantum dot systems.
- Understanding spin blockade is essential for developing quantum computing technologies.
- Previous research has explored spin blockade in various quantum dot configurations.
Purpose of the Study:
- To investigate two- and three-electron spin blockade in serially coupled vertical quantum dots.
- To identify the conditions governing spin blockade in these systems.
- To elucidate the role of non-equilibrium conditions in populating spin states.
Main Methods:
- Fabrication and characterization of three serially coupled vertical quantum dots.
- Electrical transport measurements to probe spin blockade phenomena.
- Analysis of tunneling processes, including sequential and virtual hopping.
Main Results:
- Two-electron spin blockade observed under conditions forbidding sequential tunneling but allowing virtual hopping.
- Three-electron spin blockade observed under non-equilibrium conditions with accessible triplet states.
- Distinct bias thresholds identified for accessing triplet states in two-electron spin blockade.
Conclusions:
- Non-equilibrium conditions are critical for achieving sufficient populations of triplet and quadruplet states for spin blockade.
- The findings provide insights into the control of spin states in multi-quantum dot systems.
- This research contributes to the fundamental understanding of spin dynamics in quantum dots.
Related Concept Videos
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:
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...
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...
01:20Spin–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...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:10Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the others.