Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > News > Coupling of spin and orbital motion of electrons in carbon nanotubes

March 27th, 2008

Coupling of spin and orbital motion of electrons in carbon nanotubes

Abstract:
Electrons in atoms possess both spin and orbital degrees of freedom. In non-relativistic quantum mechanics, these are independent, resulting in large degeneracies in atomic spectra. However, relativistic effects couple the spin and orbital motion, leading to the well-known fine structure in their spectra. The electronic states in defect-free carbon nanotubes are widely believed to be four-fold degenerate1, 2, 3, 4, 5, 6, 7, 8, 9, 10, owing to independent spin and orbital symmetries, and also to possess electron-hole symmetry11. Here we report measurements demonstrating that in clean nanotubes the spin and orbital motion of electrons are coupled, thereby breaking all of these symmetries. This spin-orbit coupling is directly observed as a splitting of the four-fold degeneracy of a single electron in ultra-clean quantum dots. The coupling favours parallel alignment of the orbital and spin magnetic moments for electrons and antiparallel alignment for holes. Our measurements are consistent with recent theories12, 13 that predict the existence of spin-orbit coupling in curved graphene and describe it as a spin-dependent topological phase in nanotubes. Our findings have important implications for spin-based applications in carbon-based systems, entailing new design principles for the realization of quantum bits (qubits) in nanotubes and providing a mechanism for all-electrical control of spins14 in nanotubes.

Source:
nature.com

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Discovery of nanotubes offers new clues about cell-to-cell communication July 2nd, 2015

Nanospiked bacteria are the brightest hard X-ray emitters July 2nd, 2015

Engineering the world’s smallest nanocrystal July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

Spintronics

Influential Interfaces Lead to Advances in Organic Spintronics July 1st, 2015

Emergence of a 'devil's staircase' in a spin-valve system July 1st, 2015

Spintronics advance brings wafer-scale quantum devices closer to reality June 24th, 2015

Solvent encapsulation is the trick: a solid material with spin-transition solution-like behaviour June 5th, 2015

Quantum Computing

The quantum middle man July 2nd, 2015

Freezing single atoms to absolute zero with microwaves brings quantum technology closer: Atoms frozen to absolute zero using microwaves July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

Opening a new route to photonics Berkeley lab researchers find way to control light in densely packed nanowaveguides June 27th, 2015

Discoveries

The quantum middle man July 2nd, 2015

Freezing single atoms to absolute zero with microwaves brings quantum technology closer: Atoms frozen to absolute zero using microwaves July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Announcements

Nanospiked bacteria are the brightest hard X-ray emitters July 2nd, 2015

Engineering the world’s smallest nanocrystal July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Quantum nanoscience

Freezing single atoms to absolute zero with microwaves brings quantum technology closer: Atoms frozen to absolute zero using microwaves July 2nd, 2015

The quantum spin Hall effect is a fundamental property of light June 25th, 2015

Lancaster University revolutionary quantum technology research receives funding boost June 22nd, 2015

UAB researchers design the most precise quantum thermometer to date: The device would be capable of measuring the temperature of a cell's interior June 7th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project