Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > New quantum phenomena in graphene superlattices

This is an example of the Hofstadter butterfly phenomenon.
CREDIT
The University of Manchester
This is an example of the Hofstadter butterfly phenomenon. CREDIT The University of Manchester

Abstract:
A team of Graphene Flagship researchers led by the University of Manchester reported in the journal Science showing the first new type of quantum oscillation to be reported for thirty years. This occurs by applying a magnetic field and it is the first of its kind to be present at high temperature and on the mesoscale. This research also sheds light on the Hofstadter butterfly phenomenon.

New quantum phenomena in graphene superlattices

Manchester, UK | Posted on September 18th, 2017

Quantum theory is the study of physics at the atomic and sub atomic level. It quantises energy and momentum and shows how objects are characterised as both particles and waves. Quantum oscillations can be used to map the properties of new materials in the presence of a magnetic field. This paper shows how it is possible to tune the magnetic field applied to a heterostructure comprising of graphene and boron nitride to create a whole host of different electronic materials.

The superlattice, created in graphene by its exact placement with regards to a periodically arranged boron nitride layer, interacts with the magnetic field in such a way that it is possible to tune its oscillation to manufacture bands and gaps in its electronics structure - meaning that the magnetic field can be used to tune the materials to be metallic, semiconducting or conducting.

Andre Geim, a leading member of the team and the 2010 Nobel Laureate, says "Oscillatory quantum effects always present milestones in our understanding of materials properties. They are exceedingly rare. It is more than 30 years since a new type of quantum oscillation was reported." He added "Our oscillations stand out by their extreme robustness, happening under ambient conditions in easily accessible magnetic fields."

This work also sheds further light on Hofstadter's butterfly, a fractal pattern that describes the behaviour of electrons in a magnetic field, measured experimentally for the first time in 2013 using a graphene and boron-nitride heterostructure. In the original theoretical work on which Hofstadter's butterfly is based the electrons modelled to create the fractal pattern were treated as Bloch electrons (electrons that do not interact with one another and move within a periodic electric potential within a lattice). The research shown here illustrates how these complex fractal patterns can be viewed as Langmuir quantisation which is the quantisation of cyclotron orbits (taking what is normally thought of as a circular orbit and instead viewing it as linear)

Professor Vladimir Falko, Director of the National Graphene Institute commented "Our work helps to demystify the Hofstadter butterfly. The complex fractal structure of the Hofstadter butterfly spectrum can be understood as simple Landau quantisation in the sequence of new metals created by magnetic field."

Professor Bart van Wees, Head of the Physics of Nanodevices group at the Zernike Institute for Advanced Materials, Groningen, The Netherlands added "We have always considered quantum oscillations as very brittle, easily destroyed at higher temperatures but the authors have shown that these can now be observed at room temperature, or even higher. This is good news for possible new applications of these and other systems which are based on Van der Waals stacking of two-dimensional materials."

####

For more information, please click here

Contacts:
Sian Fogden

44-012-237-62418

Copyright © Graphene Flagship

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

RELATED JOURNAL ARTICLE:

Related News Press

Physics

Leti Develops World’s First Micro-Coolers for CERN Particle Detectors: Leti Design, Fabrication and Packaging Expertise Extends to Very Large Scientific Instruments December 11th, 2017

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

News and information

Leti Develops World’s First Micro-Coolers for CERN Particle Detectors: Leti Design, Fabrication and Packaging Expertise Extends to Very Large Scientific Instruments December 11th, 2017

UCLA chemists synthesize narrow ribbons of graphene using only light and heat: Tiny structures could be next-generation solution for smaller electronic devices December 8th, 2017

Untangling DNA: Researchers filter the entropy out of nanopore measurements December 8th, 2017

Device makes power conversion more efficient: New design could dramatically cut energy waste in electric vehicles, data centers, and the power grid December 8th, 2017

JPK Instruments announce partnership with Swiss company, Cytosurge AG. The partnership makes Cytosurge’s FluidFM® technology available on the JPK NanoWizard® AFM platform December 8th, 2017

Graphene/ Graphite

UCLA chemists synthesize narrow ribbons of graphene using only light and heat: Tiny structures could be next-generation solution for smaller electronic devices December 8th, 2017

Magnetism

A material with promising properties: Konstanz scientist synthesizes an important ferromagnetic semiconductor November 25th, 2017

Quantum Physics

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

2 Dimensional Materials

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

Wrinkles give heat a jolt in pillared graphene : Rice University researchers test 3-D carbon nanostructures' thermal transport abilities November 2nd, 2017

Discoveries

UCLA chemists synthesize narrow ribbons of graphene using only light and heat: Tiny structures could be next-generation solution for smaller electronic devices December 8th, 2017

Untangling DNA: Researchers filter the entropy out of nanopore measurements December 8th, 2017

Device makes power conversion more efficient: New design could dramatically cut energy waste in electric vehicles, data centers, and the power grid December 8th, 2017

Wheat gets boost from purified nanotubes: Rice University toxicity study shows plant growth enhanced by -- but only by -- purified nanotubes December 6th, 2017

Materials/Metamaterials

Creating a new kind of metallic glass December 7th, 2017

Copper will replace toxic palladium and expensive platinum in the synthesis of medications: The effectiveness of copper nanoparticles as a catalyst has been proven December 5th, 2017

Chinese market opens up for Carbodeon nanodiamonds: Carbodeon granted Chinese Patent for Nanodiamond-containing Thermoplastic Thermal Compounds December 4th, 2017

Scientists make transparent materials absorb light December 1st, 2017

Announcements

Leti Develops World’s First Micro-Coolers for CERN Particle Detectors: Leti Design, Fabrication and Packaging Expertise Extends to Very Large Scientific Instruments December 11th, 2017

UCLA chemists synthesize narrow ribbons of graphene using only light and heat: Tiny structures could be next-generation solution for smaller electronic devices December 8th, 2017

Untangling DNA: Researchers filter the entropy out of nanopore measurements December 8th, 2017

Device makes power conversion more efficient: New design could dramatically cut energy waste in electric vehicles, data centers, and the power grid December 8th, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

UCLA chemists synthesize narrow ribbons of graphene using only light and heat: Tiny structures could be next-generation solution for smaller electronic devices December 8th, 2017

Device makes power conversion more efficient: New design could dramatically cut energy waste in electric vehicles, data centers, and the power grid December 8th, 2017

Creating a new kind of metallic glass December 7th, 2017

Copper will replace toxic palladium and expensive platinum in the synthesis of medications: The effectiveness of copper nanoparticles as a catalyst has been proven December 5th, 2017

Quantum nanoscience

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

What can be discovered at the junction of physics and chemistry October 6th, 2017

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