Related Experiment Video
Updated: May 20, 2026
14:58
Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping
Published on: June 3, 2015
Towards a quantum representation of the ampere using single electron pumps
S P Giblin1, M Kataoka, J D Fletcher
1National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, UK. stephen.giblin@npl.co.uk
Nature Communications
|July 5, 2012
Summary
Researchers developed a highly accurate semiconductor quantum dot electron pump. This device achieves unprecedented precision, paving the way for a new quantum current standard and the redefinition of the SI ampere.
Area of Science:
- Quantum physics
- Solid-state electronics
- Metrology
Background:
- Electron pumps are crucial for generating quantized electric current.
- Achieving high accuracy in quantum current standards has been a long-standing challenge.
- Previous attempts faced difficulties in balancing speed and precision.
Purpose of the Study:
- To enhance the accuracy of semiconductor quantum dot electron pumps.
- To explore the potential of specially designed gate drive waveforms.
- To develop a device suitable for realizing the SI base unit ampere.
Main Methods:
- Utilized semiconductor quantum dot devices.
- Implemented novel, specially designed gate drive waveforms.
- Performed precise measurements of generated current and accuracy.
Main Results:
- Demonstrated a semiconductor quantum dot pump with significantly improved accuracy.
- Achieved a current generation of up to 150 pA (nearly a billion electrons/sec).
- Experimentally verified current accuracy better than 1.2 parts per million (p.p.m.), approaching 0.01 p.p.m.
Conclusions:
- Specially designed gate drive waveforms dramatically improve electron pump accuracy.
- The developed pump is a strong candidate for realizing the SI ampere.
- This work advances the development of quantum current standards and metrology.
More Related Videos
Related Concept Videos
01:18Ampere's Law
A fundamental property of a static magnetic field is that it is not conservative, unlike an electrostatic field. Instead, there is a relationship between the magnetic field and its source, electric current. Mathematically, this is expressed in terms of the line integral of the magnetic field, which is also known as Ampère’s law. It is valid only if the currents are steady and no magnetic materials or time-varying electric fields are present.
Ampère's law states that for any closed looped path,...
Ampère's law states that for any closed looped path,...
01:27ATP Driven Pumps I: An Overview
ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
01:22Ampere's Law in Matter
The total current density in magnetized material is the sum of the free and bound current densities. The free current arises due to the motion of free electrons within the material, while the bound current arises due to the alignment of magnetic dipole moments.
The differential form of Ampere's law in vacuum states that the curl of the magnetic field equals the permeability times the current density. In a magnetized material, the law is modified to incorporate the free and bound current...
The differential form of Ampere's law in vacuum states that the curl of the magnetic field equals the permeability times the current density. In a magnetized material, the law is modified to incorporate the free and bound current...
02:45The Quantum-Mechanical Model of an Atom
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. Schrödinger...
01:34ATP Driven Pumps II: P-type Pumps
The P-type pumps are a large family of integral membrane transporter ATPases. They are divided into five major types based on substrate specificity, from I to V.
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
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: